BROILER CHICKEN INDUSTRY RESEARCH SERIES | RESEARCH PAPER
Chicken Age at Slaughter: What Labels Say and Federal Rules Require
A poultry class name determines which product name a chicken may carry. It does not give the bird’s hatch or slaughter date. This paper reads the federal standard, its rulemaking history and industry averages together.
Prepared for publication by Farm Animal Transparency | October 2026
“Broiler” means younger than 10 weeks. The industry’s reported 2025 average market age was 47.5 days.
| At a glance |
| Six federal classes, different rules. Cornish game hen, broiler or fryer, roaster and capon have maximum ages. The hen class requires an age above 10 months. “Cock” or “rooster” means an adult male, with no numerical age. |
| An average is not a flock’s age. The National Chicken Council, the industry’s trade association, reports an average market age of 47.5 days (about 6.8 weeks) for 2025. |
| The definitions changed. A 2011 rule (effective 2014) changed broilers from “usually under 13 weeks” to under 10 weeks. A 2016 rule (effective 2018) dropped the roaster’s 8-week minimum and set a 5.5-pound carcass minimum. |
| A missing class name is not by itself a violation. Cut-up young chickens and raw parts from young poultry may be labeled without a class term; mature-poultry parts must say so. |
| Mature hens have two sources. Hens reaching meat processing can come from table-egg flocks or from broiler-breeder flocks. |
What the class name tells a shopper
A label saying “broiler” or “fryer” identifies a chicken younger than 10 weeks that also meets specified physical characteristics. Other classes work differently: the hen class requires an age above 10 months, while “cock” or “rooster” describes an adult male without specifying a numerical age. Describing every class as an age ceiling is therefore incorrect. The class establishes eligibility for a product name; it does not supply an individual bird’s hatch and slaughter dates. [1]
Industry averages answer a separate question. The National Chicken Council (NCC), the broiler industry’s trade association, reports an average market age of 47.5 days for 2025. That is about 6.8 weeks, appreciably below the broiler class’s 10-week boundary. An average cannot establish the age of a particular flock, or show how many birds fell within a particular age interval. [5]
1. The six federal chicken classes
Section 381.170(a)(1) of Title 9 of the Code of Federal Regulations defines six chicken classes. The table summarizes the requirements; it does not reproduce every word of the regulation. Weight requirements refer to the ready-to-cook carcass, not the live bird. [1,3]
| Class | Age or maturity requirement | Other defining requirements |
|---|---|---|
| Rock Cornish game hen or Cornish game hen | Less than 5 weeks | Either sex; immature; ready-to-cook carcass no more than 2 pounds |
| Broiler or fryer | Less than 10 weeks | Either sex; tender meat, soft and pliable skin, and flexible breastbone cartilage |
| Roaster or roasting chicken | Less than 12 weeks | Either sex; ready-to-cook carcass at least 5.5 pounds; specified meat, skin and cartilage characteristics |
| Capon | Less than 4 months | Surgically neutered male; specified meat and skin characteristics |
| Hen, fowl, baking chicken or stewing chicken | More than 10 months | Adult female; meat less tender than a roaster’s and a nonflexible breastbone tip |
| Cock or rooster | Adult; no numerical age stated | Male; coarse skin, tougher and darker meat, and a nonflexible breastbone tip |
Source: Current 9 CFR 381.170(a)(1). [1]
2. Why the definitions changed
FSIS revised several poultry classes in a final rule published November 3, 2011, effective January 1, 2014. The agency explained that genetic improvements and management changes had shortened grow-out periods and changed market characteristics. The broiler definition changed from “usually under 13 weeks” to less than 10 weeks. The rule also set the Cornish game hen limit below five weeks and the capon limit below four months. [3]
That rule initially defined a roaster as eight to twelve weeks old with a ready-to-cook weight of at least five pounds. A second final rule, published April 13, 2016 and effective January 1, 2018, removed the eight-week minimum and raised the carcass-weight minimum to 5.5 pounds. Thus, a current roaster label does not establish that the chicken reached eight weeks of age. [3–4]
3. Market age and weight are different measures
NCC’s historical performance series shows substantial changes in both market age and live weight. More recent increases in weight have not required a return to the much longer grow-out periods reported for the early industry. The series is industry-published data, attributed by NCC to USDA or other sources; it is not a record of the birds in a specific retail package. [5]
| Year | Average market age | Average live market weight |
|---|---|---|
| 1925 | 112 days | 2.50 pounds |
| 1950 | 70 days | 3.08 pounds |
| 1990 | 48 days | 4.37 pounds |
| 2010 | 47 days | 5.70 pounds |
| 2025 | 47.5 days | 6.63 pounds |
Source: NCC, U.S. Broiler Performance. [5]
4. What genetic research establishes
A controlled comparison by Zuidhof and colleagues, published in 2014, raised meat-control strains unselected since 1957 and 1978 alongside a commercial Ross 308 strain representing 2005. The birds received a common contemporary nutritional program and were followed to 56 days. The authors reported growth increasing by more than 400% and feed conversion improving by approximately 50% across the represented selection histories. [6]
This experiment provides evidence of the effects of genetic selection under its study conditions. It does not establish the slaughter age, breed, health or welfare of every commercially raised chicken. Nor should it be used to assign the same growth performance to all breeding lines. A package-specific age claim still needs evidence about that product’s actual supply. [6]
5. Mature hens have more than one production history
Older hens entering meat processing can come from table-egg flocks or from broiler-breeding flocks that produce hatching eggs. USDA’s market terminology distinguishes light hens associated with table-egg production from heavy breeder hens. It is therefore inaccurate to describe all mature hens as coming from the table-egg supply chain. [7]
A 2016 review by Bain, Nys and Dunn described flock replacement at approximately 72 weeks and breeding objectives for longer laying cycles, including 500 eggs by 100 weeks. Those observations and goals belong to that review’s period and context. They are not a current national estimate of U.S. hen slaughter age. The regulatory threshold above 10 months also does not specify a farm’s flock-replacement schedule. [1,8]
6. When a class name may be omitted
Under 9 CFR 381.117(b), poultry product names generally include the kind and an age or class designation. There are specific exceptions. Ready-to-cook cut-up young chickens and halves may use “chicken” without a class term. Raw parts from young poultry can use the kind and part name, such as “chicken breast.” Parts from mature poultry must include the class name or “mature.” Cooked or heat-processed products have a further exception: the kind is required, but the class or “mature” designation is not. [2]
Consequently, the absence of a class term on raw chicken parts does not, by itself, show a labeling violation. A name permitted for young poultry conveys less precise information than a stated slaughter age in days. The regulation establishes the naming rules; it does not tell us what proportion of products on sale omit class names. [2]
7. What FAT should record
For transparency review, FAT should distinguish the class printed on the package, the age or maturity implication of that class, any additional numerical slaughter-age claim, and the evidence supporting that additional claim. A cock or rooster designation should not be converted into an invented numerical range. A broiler designation should not be displayed as an exact slaughter age. [1–2]
Where a producer supplies flock records or an audit, FAT should identify the document, the flocks or products it covers, its date, and the age information it substantiates. Where only a class name is available, the review should retain that limited meaning. The NCC average can provide clearly dated context, without substituting for product-specific information. [1–2,5]
Sources
- Electronic Code of Federal Regulations. 9 CFR 381.170: Standards for kinds and classes, and for cuts of raw poultry. Current text consulted October 17, 2026.
- Electronic Code of Federal Regulations, reproduced by Cornell Legal Information Institute. 9 CFR 381.117: Name of product and other labeling. Current text consulted October 17, 2026.
- USDA FSIS. Classes of Poultry, final rule, 76 FR 68058–68064. November 3, 2011; effective January 1, 2014.
- USDA FSIS. Classes of Poultry, final rule, 81 FR 21706. April 13, 2016; effective January 1, 2018.
- National Chicken Council. U.S. Broiler Performance. Industry trade-association series; consulted October 17, 2026.
- Zuidhof MJ, Schneider BL, Carney VL, Korver DR, Robinson FE. Growth, efficiency, and yield of commercial broilers from 1957, 1978, and 2005. Poultry Science. 2014;93(12):2970–2982. doi:10.3382/ps.2014-04291.
- USDA Agricultural Marketing Service. Poultry and Egg Terms. Consulted October 17, 2026.
- Bain MM, Nys Y, Dunn IC. Increasing persistency in lay and stabilising egg quality in longer laying cycles. What are the challenges?. British Poultry Science. 2016;57(3):330–338. doi:10.1080/00071668.2016.1161727.
Working paper. First prepared July 15, 2026; revised October 17, 2026, with sources checked through that date. Corrections welcome: dirkadams@farmanimaltransparency.com.