I did some more research and came up with a much more complicated but focused formula. Instead of using 18 week cycles, which leaves plenty of room for missed variables, I decided to view the problem week by week.
The good news: the Egg layer population isn’t crashing out.
The bad news: previously available for retail eggs are being used to replenish egg layer populations.
TLDR, what’s the situation today?
Assuming most growers are attempting to replace all bird losses and increase their population to the three-year median level, my model estimates the Breeder Stock population in the US is sitting around 3,774,627 a decrease of 5,373 from 3,780,000 in Jan 2024.
The same model suggests Table Egg Layer population is currently at 302,954,162 a decrease of 8,045,838 from 311,000,000 in Jan 2024.
Taking a look at last week: 7,505,025 (39.22%) Breeder Stock eggs were used to replenish lost Breeders and Table Egg Layers instead of going to other uses such as Retail and Live sales.
Table Egg Layers laid 1,846,019,083 Eggs, 5.12% short if there were no Avian flu deaths, just 96.09% of their production if a median bird population was kept.
A total of 2,383,952 Table Eggs were lost this week. 22,501,221 so far in 2025.
Terms
Table Egg Layers are birds that lay Eggs meant for retail/further processing.
Breeder Stock Hens are birds breed to produce fertilized eggs that hatch into Table Egg Layers. If their numbers decline, so does the future population of Table Egg Layers and therefore the inventory of Retail Eggs.
Pullets are Chicks that haven’t matured into Table Egg Layers yet.
Limited Data
The USDA does not currently report Avian Flu cases for Breeder Stock Hens. However, Breeder stock Hens make up 1.21% of birds related to Table Egg Laying. So we will calculate their exposure to Avian Flu using that percentage against all Table Egg Layers reported on the Avian Flu numbers.
Assumptions, Averages and Medians
For 2022-2024 the Median number of Table Egg Layers was 315,963,300 with Breeding Stock at 3,840,480. They make up 98.79% and 1.21% of the Egg laying population respectively. These are the population numbers we will start at and attempt to maintain.
Per the USDA, for every 100 Egg Layers there is an average of 80 Eggs laid daily.
Let’s assume there is a 60% replacement rate each year due to old age, declining productivity and other natural causes (not Avian Flu). Meaning, 60% of the years starting population will need to be replaced by year end.
Assume an 85% Hatchability rate for all Eggs.
50% chance of either Male or Female Chick for all Eggs.
Chick survival rate of 90%.
Pullets/Chicks take 18 weeks (126 Days) to Mature into Egg laying Hens.
Formulas
Without getting too complicated.
We have two running populations: Breeder Stock and Table Layers. Each day we subtract their respective share of the Avian Flu deaths and the annual 60% replacements. [(Population * 60%)/365] We then add the matured Pullet population minus any Pullet Avian Flu deaths.
Breeder Stock Egg production is determined by a quick formula outlined above. 80 Eggs for every 100 layers, 93% chance of Fertilization and 85% Hatchability. [(((Population/100)*80)*93%)*85%)
Table Egg Layer Egg production is determined slightly differently. 80 Eggs for every 100 layers and a 95% chance the Egg is usable. This allows 5% uncertainty for accidents/issues.
Eggs to Pullets are estimated by adding up several variables. Birds needing replacements, Avian Flu Deaths, and median population refill. These are subtracted from the Breeder Stock Egg Production and held onto for 18 weeks to mature.