ISA Brown Laying Hen: Egg Production Chart & Care Guide
Scientific reference mapping ISA Brown laying curves, docility, climate adaptability, and nutrition.
Scientific Overview
The ISA Brown is a world-famous brown egg hybrid laying hen produced by Hendrix Genetics. Celebrated for its docility, strong eggshell quality, high egg numbers (300+ brown eggs per hen housed), and adaptability to both intensive cage and extensive free-range housing, the ISA Brown is the most popular brown layer worldwide.
ISA Brown Layer Overview & Definition
The ISA Brown is defined as a sex-linked hybrid brown egg laying chicken (Rhode Island Red x Rhode Island White cross) bred by Hendrix Genetics for high egg persistency, dark brown eggshells, and docile temperament.
The sex-link genetic trait allows day-old chicks to be sexed easily by feather color: female chicks are reddish-brown while male chicks are white.
ISA Brown Production Curve & Performance Chart
Standard production objectives for an ISA Brown commercial flock:
- Age at 50% Lay: 144 days (20.5 weeks)
- Peak Hen-Day Production: 93–96% at 25–27 weeks
- Eggs per Hen Housed (72 wks): 305–315 brown eggs
- Average Egg Weight: 62.5–64.5 grams
- Livability (18–72 wks): 94–96%
Monitor your lay rates with our Hen-Day Production Calculator.
Feed Intake & Adaptability
ISA Brown adult layers consume 110–115g of complete layer feed daily under temperate conditions. They possess strong heat tolerance and robust feathering, performing reliably across battery cages, aviary systems, and outdoor free-range pastures. Explore backyard care in our Backyard Poultry Guide.
All scientific data, diagnostic criteria, and performance benchmarks presented on this page are derived from published peer-reviewed journals and official veterinary codes:
- Avian Pathology & Diagnostics: World Organisation for Animal Health (WOAH, 2023). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France.
- Poultry Diseases & Histology: Swayne, D.E., et al. (2020). Diseases of Poultry (14th ed.). Wiley-Blackwell / American Association of Avian Pathologists.
- Nutrition & Feed Chemistry: Leeson, S. & Summers, J.D. (2001). Commercial Poultry Nutrition (3rd ed.). University Books, Guelph, Ontario.
- Commercial Breed Standards: Aviagen (2024). Ross 308 & Cobb 500 Broiler Performance Objectives. / Lohmann Breeders (2024). Lohmann Brown Management Guide.