Egg Week


USDA Weekly Egg Price and Inventory Report, September 13th 2023.


Market Overview

  • The average wholesale unit revenue values for Midwest Extra-large and Large were down 1.3 percent this past week but now conform to seasonal summer values. Medium size was unchanged from last week. This past week shell egg inventory was up 4.0 percent, following a rise of 0.2 percent the previous week. The relatively small increase in inventory was recorded despite presumed higher demand with stable to lower shelf prices for generics. Supply is higher due to a small but progressive weekly increase in the national flock through August and continuing into September. Chains have narrowed the spread between delivered cost and shelf price and lower stock levels should be anticipated. Eggs are now highly competitive in price against the comparable costs for other protein foods especially as retail margins imposed by some chains have fallen sharply due to competition from deep discounters.
  • Total industry inventory was up by 3.3 percent overall this past week to 1.76 million cases with a concurrent 0.1 percent increase in breaking stock, compared to an decrease of 2.3 percent last week. Demand for egg products is presumably higher during summer due to travel and entertainment. Egg products are required for the food service and manufacturing sectors but exports are depressed Volume this past week was higher despite an increase in the shelf prices for shell eggs. Wholesale prices compare with 2020 and 2021, also characterized by low ex-plant unit revenue. Benchmark prices were approximately $0.80 per dozen lower than the corresponding week in 2022, that was influenced by flock depletions following HPAI.
  • It is now apparent that the inventory held by chains and other significant distributors may be more important over the short term in establishing wholesale price than the USDA regional inventory figures. Changes in stock held by DCs and in the pipeline as determined by weekly orders are probably responsible for relatively small cyclic fluctuation in weekly industry stock.
  • Low unit revenue compared to pre-HPAI will persist through September. Sporadic outbreaks of HPAI are unlikely given that the seasonal Fall migration of waterfowl is two months away. The number and extent of future possible outbreaks during late fall and early winter of 2023 cannot be assessed until more information is available concerning the molecular and field epidemiology of the 2022 spring and fall waves of HPAI. The USDA has yet to identify specific modes of transmission for the 2022 epornitic including possible airborne spread from wild birds and their excreta over short distances.
  • The current relationship between producers and chain buyers based on a single commercial price discovery system constitutes an impediment to a free market. The benchmark price appears to amplify both downward and upward swings as evidenced over the past year. A CME quotation based on Midwest Large, reflecting demand relative to supply would be more equitable. If feed cost is determined by CME ingredient prices then generic shell eggs should be subject to a Midwest Large quotation.
  • According to the USDA the U.S. flock in production was up 0.2 percent or 0.6 million hens to 312.4 million during the week ending September 13th. The total flock of 318.8 million hens included about 5.0 million molted hens that will resume lay during coming weeks plus 4.0 to 5.0 million pullets attaining production. Given the latest figures it is estimated that the producing flock is still 4 to 5 million hens lower than before the onset of HPAI.
  • The ex-farm price for breaking stock was unchanged this past week at 93 cents per dozen.Checks delivered to Midwest plants were up 2.6 percent to 80 cents per dozen. Prices for breaking stock will remain low until there is a substantial increase in wholesale price for shell eggs.


The Week in Review




According to the USDA Egg Market News Reports released on September 11th the Midwest wholesale price (rounded to one cent) for Extra-large was down 1.3 percent from last week to $1.57 per dozen. Large was down 1.3 percent $1.55 cents per dozen. Mediums were unchanged at $1.11 per dozen delivered to DCs. Prices should be compared to the USDA benchmark average 6-Region blended nest-run cost of 82.9 cents per dozen as determined by the USDA for August 2023. This excludes provisions for packing, packaging materials and transport, amounting to 57 cents per dozen determined in mid-2023, from an EIC survey with low response. Currently producers of generic shell eggs are operating at break-even or negative margins depending on region and customer-supply agreements. The progression of prices during 2023 to date is depicted in the USDA chart reflecting three years of data, updated weekly.

The September 11th 2023 edition of the USDA Egg Market News Report documented an increase of 5.8 percent in the USDA Combined Region value rounded to the nearest cent, to $1.65 per dozen delivered to warehouses for the week ending September 8th 2023. This average price lags current benchmark Midwest weekly values by one week. The USDA Combined range for Large in the Midwest was $1.57 per dozen. At the high end of the range, the price in the South Central region attained $1.73 per dozen. The USDA Combined Price last week was approximately 15 cents per dozen above the 3-year average of $1.50 per dozen. This past week Midwest Large was approximately $0.60 below the corresponding week in 2022 elevated by losses due to HPAI.


Flock Size 


According to the USDA the number of producing hens reflecting September 13th (rounded to 0.1 million) was up 0.6 million hens (0.2 percent) to 312.4 million. The total U.S. flock includes about 5 million molted hens due to return to production with approximately 4 to 5 million new pullets reaching maturity each week based on USDA monthly chick-hatch data for 20-weeks previously. The increase is offset by routine flock depletion in addition to residual losses during the Fall phase of the 2022 HPAI epornitic. Based on inventory level and prices the hen population producing eggs should now be in relative balance with consumer demand. Industrial and food service off-take although increasing, has not reverted to pre-COVID levels. Prices will continue to fluctuate and are expected to stabilize at a low seasonal level through the remainder of September 2023.


According to the USDA the total U.S. egg-flock on September 13th was up 0.6 million hens (0.2 percent) to 318.8 million including second-cycle birds and those in molt. The difference of 6.4 million hens between flocks in production and total hens is an approximate figure but denotes that many molted hens will resume production after molt. Despite benchmark wholesale prices up for three consecutive weeks older flocks have been molted or depleted. At present there are 4 to 5 million fewer hens in the total flock with the difference equivalent to about 1.5 percent of the pre-HPAI national flock of 325 million hens.




Cold storage stocks of frozen products in selected centers on September 11th 2023 atained 2.517 million pounds (1,144 metric tons), and down 0.8 percent from the inventory of 2.536 million lbs. on September 1st 2023. The monthly USDA Cold Storage Report below quantified an increase in the actual total stock level at the end of July.


The most recent monthly USDA Cold Storage Report released on August 23rd 2023 documented a total stock of 29.6 million pounds (13,471 metric tons) of frozen egg products on July 31st 2023. This quantity was up 28.9 percent from the July 31st 2022 value of 23.0 million pounds. July 31st 2023 frozen egg inventory was up 8.3 percent from the previous month ending June 30th 2023 attributed to presumably lower demand. Compared to July 31st 2022 yolk inventory was up 39.8 percent to 973 million lbs. on July 31st 2023.


A total of 88.0 percent (26.1 million lbs.) of combined inventory comprised the categories of “Whole and Mixed” (43.2 percent) and “Unclassified” (44.8 percent). The lack of specificity in classification requires a more diligent approach to enumerating and reporting inventory by the USDA.


Shell Inventory


The USDA reported that the national stock of generic shell eggs effective September 11th 2023 was up 3.3 percent over the previous week. The relative movement of stock over the past three months suggests an increase in consumer demand. Combined with breaking stock, the total inventory of shell eggs in industry cold rooms is now at a rounded level of 1.76 million cases (1.70 million last week; 56,100 cases higher this week). The U.S. population of laying hens at this time is influenced by a small number of older birds previously culled during the fall phase of the 2022 HPAI epornitic and includes the population unaffected by HPAI, flocks retained after molting (with an anticipated increase in this category based on prevailing egg prices) and started pullets from chick placements during late March 2023. Going forward, younger hens will assume a larger proportion of the national flock as more flocks are placed compensating for the flocks depleted due to HPAI.


Three of six USDA Regions reported higher stock levels this past week. The regions are listed in descending order of stock: -

  • The Midwest Region was up 4.8 percent from the previous week to 488,200 cases.
  • The South Central Region was up 9.5 percent to 295,400 cases
  • The Southeast Region was up 5.2 percent to 270,900 cases
  • The Northeast Region was down 0.1 percent to 179,500 cases
  • The Southwest Region was down 1.8 percent to 137,200 cases.
  • The Northwest Region was down 4.3 percent to 70,100 cases


The total USDA six-area stock of commodity eggs comprised 1,755,300 cases (1,699,200 cases last week), up 3.3 percent, of which 82.1 percent were shell eggs (81.5 percent last week). The inventory of breaking stock was up 0.1 percent to 314,100 cases. Shell egg inventory was up 4.0 percent attaining 1,441,200 cases. This denotes relatively stable demand but tending to an increase during September. Retailers are hopefully restocking last week.


The reduced level of breaking stock over the past week is attributed to increased consumer demand, conversion to egg powder and liquids for export and inventory with higher demand for liquids by industry and food service. The average price for Midwest checks and breaking stock combined was 54.8 percent of the average value of Midwest Extra-large and Large shell eggs (51.4 percent for previous week) consistent with disproportionately lower prices for breaking stock and checks compared to shell eggs with a relatively greater spread in prices this past week. The differential can be compared to 80.0 percent in April 2022 reflecting the initial period of high demand for both shell eggs and breaking stock after the onset of HPAI. This past week the wholesale prices for Midwest Extra-large and Large shell eggs were 1.3 lower compared to the combination of breaking stock and checks that were 1.3 percent higher from the previous week. This demonstrates the respective demands for shell eggs and egg products. There is interconnectivity of the packing and breaking segments of the egg industry under circumstances of extreme disturbances in either supply (lower due to HPAI in 2022) or demand (higher during COVID in 2020). The price for breaking stock and for checks is influenced by the relative demand for generic shell eggs and contract obligations with breakers.


On September 11th 2023 the inventory of other than generic eggs amounting to 458,700 cases (up 3.0 percent from last week at 445,500 cases) among three categories (with the previous week in parentheses) comprised: -

  • Specialty category, up 8.5 percent to 42,200 cases. (Was down 3.4% to 38,900 cases)
  • Certified Organic, down 0.3 percent to 102,500 cases. (Was down 1.5% to 102,800 cases)
  • Cage-Free category, up 1.8 percent to 314,000 cases. (Was down 1.6% to 308,300 cases)


Demand for cage-free product will not increase materially over the long term while generic eggs from caged flocks and some surplus down-classified cage-free eggs are on the shelf at $2.00 to $2.30 per dozen during normal supply and demand conditions. Currently there is a wide differential in shelf price between generics compared to the considerably higher priced omega-3 enriched, cage-free, free-range and pasture-housed products. That the higher priced egg categories will lose demand is supported by the findings of the comprehensive review relating to the transition from cages to alternative systems.*


Existing and proposed individual state legislation mandating sale of only cage-free eggs will support most of the completed and anticipated transition from cages but total re-housing will not be completed by the beginning of 2025, less than 16 months away and ultimately never as projected by most industry observers. The constitutional status of Proposition #12 was confirmed by SCOTUS in a May 11th 2023 decision with specific reference to the dormant Commerce Clause relating to interstate trade. A legislative initiative (the EATS Act) may be incorporated into the 2023 Farm Bill, to limit the impact of Proposition #12 on sows housed for pork production. Many retail chains are ‘renEGGing’ on or extending their time commitments to achieve an acceptable transition to cage-free eggs despite coercion by animal welfare groups. With the current proportion of non-caged flocks and lower prices for generic cage-derived eggs, cage-free eggs are surplus to demand in some areas. Cage-free eggs are becoming a commodity in many markets subjected to the same price pressures as generic eggs from caged hens. Growth in demand for organic product has been relatively static for months. Stock in this category has exceeded 100,000 cases over the past four weeks but this quantity represents approximately three days production. Long-term demand for cage-free eggs is influenced by the relative shelf prices of the category in comparison with generic white-shelled eggs from caged flocks. Inventory of this category exceeded 300,000 cases for the seventh consecutive week, but effectively is working stock given weekly production of 1.7 million cases of this category. At the other end of the price range, consumers will purchase less-expensive brown cage-free product over organic eggs when there is a differential in price greater than about $1.20 per dozen under normal conditions of supply and demand. Similarly, consumers will traditionally purchase white-shelled generic eggs in preference to white or brown-shelled cage-free with a differential of over $1.20 per dozen.

*Caputo,V. et al The Transition to Cage-Free Eggs. February 2023


A comprehensive structured market research project on cage-free eggs has provided an indication of consumer willingness to pay for this attribute. The industry requires a study on other aspects including shell color, GM status and nutritional enrichment. Above all, agricultural economists should evaluate the impact of disruption in supply and demand arising from large-scale depopulation following HPAI in 2015 and for the 2022 HPAI epornitic extending through partial restoration of hen numbers but a disproportionate decline in wholesale price during the first quarter of 2023.




USDA-AMS posted the following national shell egg prices as available, for September 8th 2023 in the Egg Markets Overview report for dozen cartons with comparable prices in parentheses for the previous week: -



Large, in cartons generic white: $1.07 Up 4.9 percent ($1.47)

Large, in cartons cage-free brown: $2.86 Down 19.2 percent ($3.14)



Large C-F, California in Cartons: $2.13 Up 2.4 percent ($2.08)

National loose, (FOB dock): $1.02 Down 18.4 percent ($1.25)

NYC in cartons to retailer: $1.64 Down 3.5 percent ($1.65)


Regional in cartons to warehouse September 8th

Midwest $1.57 Up 6.1 percent ($1.48)

Northeast $1.62 Up 5.9 percent ($1.53)

Southeast $1.69 Up 7.0 percent ($1.58)

South Central $1.73 Up 6.1 percent ($1.63)

Combined $1.65 Up 5.8 percent ($1.56)



USDA Certified Organic, Brown, Large: $5.12 ($5.57)

Cage-Free Brown, Large: $3.99 ($2.99)

Omega-3 Enriched Specialty, White, Large: $2.49 ($2.91)

Generic White, Large Grade A $1.06 ($1.40)

Generic White, Large Grade A featured $1.07 ($1.02)


The advertised price for Large white grade A over 991 stores posted for the week ending September 14th was $1.06 per dozen, down $0.34 per dozen or 24.3 percent from the previous week at $1.40 per dozen. Shelf prices will influence demand for generic categories given their availability and the comparison with higher advertised and actual shelf prices for specialty and cage-free brown eggs. Current supply was probably slightly higher compared to demand this past week. Independent producers continue to divert shell eggs from breaking to market. Large integrated companies and packers continued to deliver to DCs and chains continue to place orders to restock.


The USDA benchmark-advertised retail price for certified organic for the past week was $5.12, down $1.45 per dozen or 8.1 percent from $5.12 per dozen based on 2,013 stores. The USDA advertised price of $3.99 per dozen was posted for cage-free brown during the past week (240 stores), up $1.00 per dozen or 33.4 percent. The price differential between USDA organic and cage-free brown of $1.13 cents per dozen favors purchase of certified organic over cage-free brown eggs. Week-to-week fluctuations expressed as a percentage can be expected in the stock of specialty and organic eggs based on the small base of these categories. There was an upward trend in inventory of cage-free and other specialty categories this past week as price-conscious consumers purchased generic eggs from caged flocks at lower prices. The inventory of organic eggs was almost unchanged after a large accumulation suggesting a consumer response to price reduction for the organic category.


The price of cage-free brown at $3.99 per dozen was $1.87 per dozen higher (88.2 percent) compared to cage-free white (369 stores) at $2.12 per dozen.


USDA data on advertised promotional retail prices this week indicated an advertised shelf price of $1.06 per dozen for generic Large white compared to a composite wholesale price of $1.65 per dozen delivered to DCs. This represented a theoretical U.S. retail loss of 557 percent on average (last week a negative margin of 11.4 percent) for featured categories. Demand will increase as retailers restrict markups.


Certified organic were promoted this past week at 31.0 percent of the total, consistent with high inventory, (last week 15.3 percent). Omega-3 enriched comprised 25.4 percent of features with high inventory (64.2 percent last week) with cage-free at 9.1 percent despite high stock (7.0 percent last week). Large at 33.6 percent (59.7 percent last week) comprised the predominant generic size featured. This confirms that retailers promote any category if available in excess of demand.


USDA Cage-Free Data


According to the latest monthly USDA Cage-free Hen Report released on September 1st 2023, the number of certified organic hens during August increased by an unexpected 0.7 million or 3.8 percent from July 2023 to 18.9 million, (rounded to 0.1 million).


The USDA reported that the cage-free (non-organic) flock in August 2023 was unexpectedly up 2.7 percent from July 2023 to 105.3 million, (rounded to 0.1 million).


According to the USDA the population of hens producing cage-free and certified organic eggs in August 2023 comprised: -

Total U.S. flock held for USDA Certified Organic production = 18.9 million (18.2 million in Q2 2023).

Total U.S. flock held for cage-free production = 105.8 million (103.3 million in Q2 2023).

Total U.S. non-caged flock =124.7 million (121.5 million in Q2 2023).


This total value represents 38.4 percent (July, 37.4 percent) of a nominal 325 million total U.S. flock pre-HPAI (but 39.3 percent of the national flock after HPAI mortality to an August complement of 318 million). Hens certified under the USDA Organic program have decreased in proportion to cage-free flocks since Q1 of 2021.


The accuracy of individual monthly values is questioned given a history of either sharp changes or no change in successive months as documented over the past two years. Precise quarterly reports would be more suitable for the industry in planning expansion and allocation of capital.

Processed Eggs


For the processing week ending September 9th 2023 the quantity of eggs processed under FSIS inspection during the week as reported on September 13th 2023 was down 1.1 percent compared to the previous processing week to a level of 1,514,252 cases, (1,531,022 cases last week). The proportion of eggs broken by in-line complexes was 55.2 percent (53.8 percent in-line for the previous week). The differential in price for shell sales and breaking will determine the movement of uncommitted eggs. This past week 69.5 percent of egg production was directed to the shell market, (69.1 percent for the previous week) responding to the differential in prices paid by breakers and packers. Breaking stock inventory was up 0.1 percent this past week to 314,100 cases with continued diversion to shell-egg markets. Apparent demand from QSRs and casual dining is at stable to slightly higher levels. There is continued demand from baking and eat-at-home despite the weekly fluctuation in the inventory of breaking stock. During the corresponding processing week in 2022 in-line breakers processed 51.4 percent of eggs broken.


For the most recent monthly report, revised data for week ending September 9th 2022, yield from 7,808,823 cases (6,198195 cases last month) denoted an increase in demand for liquid over the period July 30th through September 2nd 2023. Edible yield was 38.2 percent, distributed in the following proportions expressed as percentages: - liquid whole, 61.2; white, 23.5; yolk, 11.5; dried, 3.7.


All eggs broken during 2022 attained 76.22 million cases, 2.0 percent less than 2021. Eggs broken in 2023 to date amounted to 53.85 million cases, 0.1 percent less than the corresponding period in 2022. This is attributed to stable demand for egg liquids from retail, food service and QSRs and casual dining restaurants. The market is constrained by economic uncertainty following the ending of COVID supports, inflation, high credit card interest rates and purchasing of only essentials by consumers




Breaking Stock


The average rounded price for breaking stock was unchanged this past week at an average of $0.93 per dozen with an extreme range of $0.85 to $1.00 per dozen delivered to Central States plants on September 4th. Checks were up 2.6 percent this past week to an average of $0.80 per dozen over the most frequent range of $0.77 to $0.79 per dozen suggesting that the market for breaking stock is generally paralleling shell eggs.


Shell Eggs


The USDA Egg Market News Report dated September 11th 2022 confirmed that Midwest wholesale prices for Extra-large and Large were up on average by 1.3 percent. Medium size was unchanged this past week. Consecutive weekly higher prices coupled with stock fluctuating over a narrow range, suggests that the market is plateauing having bottomed six weeks ago. The following table lists the “most frequent” ranges of values as delivered to warehouses*: -



Current Week

Previous Week

Extra Large

155-158 cents per dozen

157-160 Down 1.3%


153-156 cents per dozen

158-149 Down 1.3%


109-112 cents per dozen




Breaking stock

85-100 cents per dozen



79- 81 cents per dozen

77-79 Up 2.6%

*Store Delivery approximately 5 cents per dozen more than warehouse price


The September 11th 2023 Midwest Regional (IA, WI, MN.) average FOB producer price, for nest-run, grade-quality white shelled Large size eggs, with prices in rounded cents per dozen was down 5.0 percent from last week, (with the previous week in parentheses): -

  1. $1.37 ($1.43), (estimated by proportion): L. $1.32 ($1.39): M. $0.91 ($0.91)


The September 11th 2023 California price per dozen for cage-free, certified Proposition #12 compliant Large size in cartons delivered to a DC, (with the previous week in parentheses) was down 0.9 percent from last week.

  1. $2.14 ($2.15); L. $2.11 ($2.13); M. $1.65 ($1.53)


Shell-Egg Demand Indicator


The USDA-AMS Shell Egg Demand Indicator for September 13thwas down 2.8 points from the last weekly report to +1.9 with a 3.3 percent increase in total inventory and a 4.0 percent higher shell inventory from the past week as determined by the USDA-ERS as follows: -


Productive flock

312,396,641 million hens

Average hen week production

81.8%(was 81.8 %)

Average egg production

255,569,964 per day

Proportion to shell egg market

69.5% (was 69.1%)

Total for in-shell consumption

 489,573 cases per day

USDA Shell Inventory

1,441,200 cases

26-week rolling average inventory

4.72 days

Actual inventory on hand

4.63 days

Shell Egg Demand Indicator

+1.9 points (was +4.7 on September 6h 2023)


See the text, tables and figures and the review of production data and prices comprising the USDA Report for August 2023 in this edition and the 4th Quarter and FY 2023 results for Cal-Maine Foods under the STATISTICS tab.


Dried Egg Products


The USDA extreme range in prices for dried albumen and yolk products in $ per lb. was released on September 8th 2023. Data posted by the USDA is incomplete but available values are depicted for the past week and in parentheses for the previous week and also past months to illustrate the trend in prices influenced by HPAI depopulation and subsequent repopulation:


Whole Egg

$6.00 to $8.00

($6.00 to 8.25)

Average April $11.28

May $ 9.15

June $ 7.09

July $ 6.91

August $ 7.08


No quotation, past week

($4.25 to $5.80)


Average April $ 9.85

May $ 7.67

June $ 5.85

July $ 5.70

August $ 5.16

Spray-dried white

No quotation, past week

Average Dec. $14.18

Jan. $14.18

Feb-August. No release


No quotation, past week



Frozen Egg Products


The USDA range in prices for frozen egg products in cents per lb. based on the extreme range on September 1st compared to the previous week were generally down in price:-


Whole egg down 0.5 percent; Whites, down 10.7 percent; Yolks, up 2.2 percent;


This indicated oversupply relative to demand from the manufacturing and food service sectors: -

Whole Egg1

$0.94 - $1.03

$0.88 - $1.15


$1.04 - $1.10

$1.02 - $1.35

Average for Yolks1

$1.97 - $2.02

$1.75 - $2.15

  1. extreme range


August averages (July): Whole. $1.02, ($1.04); Whites, $1.19, ($1.18); Yolks, $1.96, ($2.00).


Liquid Egg Products

Values for the past week for certified truckload quantities were not released. August averages are compared with July values (cents per lb.) with July 2023 values in parentheses are: -


Whole, $0.71, ($0.68); Whites, $0.74 ($0.74); Yolks, $1.72, ($1.72).


The USDA has not released a report on dried egg inventory since March 13th 2020 due to inability to obtain data from producers, and will not issue reports for the immediate future.




There have been no reports of HPAI in commercial egg-producing or broiler flocks since December 2022. Cases expected during the first quarter of 2023 fortunately did not materialize, possibly relating to the absence of actively shedding migratory birds in areas with commercial poultry. Only a few outbreaks have been recorded among turkeys and backyard farms year-to-date in addition to free-living predatory and scavenging carnivorous mammals. Given the risks and consequences of infection it will be necessary to continue to maintain high levels of structural and operational biosecurity through summer with intensification into fall months. HPAI is now frequently diagnosed in breeding colonies of marine birds in costal areas of Europe and sporadically in commercial flocks. This has implication for trans-Atlantic dissemination following the pattern in the 4th quarter of 2021 extending into 2022.


Approximate losses in commercial flocks with confirmed HPAI and updates during the 2022 epornitic included:-

  • 2,900,000 broilers on 18 farms in 7 states For 2023 to date losses are 450,000
  • 330,000 broiler breeders on 11 farms in 6 states.
  • 9,900,000 turkeys including a few breeder flocks on 231 farms in 7 states. For 2023 to date losses are approximately 250,000 with two incident cases in the Dakotas during mid-May.
  • 44,000,000 egg-production hens in total with 95 percent on 22 large complexes above 0.5 million in addition to 1,070,000 pullets with a total of 41 locations in 11 states. Pullet mortality does not include “at risk” replacements depleted on affected complexes with contiguous pullet rearing.


Backyard flocks that are allowed outside access will continue to be at risk of infection in the U.S. These small clusters of birds in suburban areas are of minimal significance to the epidemiology of avian influenza as it affects the commercial industry. Backyard flocks serve as indicators of the presence of virus among free-living birds as evidenced by ongoing outbreaks in commercial poultry flocks across the U.S.


The USDA-APHIS published a report on the results of epidemiologic studies* available on July 25th. Results on 18 case farms and 22 control farms suggested higher risk of infection associated with the presence of a farm in a control zone, proximity of wild birds, mowing or bush hogging vegetation adjacent to the farm, and off-site disposal of routine mortality. These factors suggest possible aerogenous introduction of virus shed by wild birds onto farms over short distances. Protection was enhanced by effective structural and operational biosecurity. The validity of findings was limited by the confounding inherent to the diversity in size of flocks incorporated into the case-control study and deriving data from a 26 page questionnaire by telephone survey, months after outbreaks, introducing recollection bias and responder fatigue.

*Green, A. et al Investigation of risk factors for introduction of highly pathogenic avian influenza H5N1 virus onto table egg farms in the United States, 2022: a case-control study. Frontiers in Veterinary Science. Doi: 10.3389/vets.2023.1229008


It is hoped that APHIS recognises the need to provide the industry with science-based recommendations to prevent HPAI in subsequent outbreaks. This presumes prompt analysis and reporting of whatever field and molecular epidemiology that is collected. The Agency is also advised to plan epidemiologic field studies and allocate personnel and other resources in anticipation of a fall resurgence in HPAI.