Choosing the Right Broiler Breed for Your Operation
Broiler breed selection is one of the most consequential decisions a grower makes, yet it is often determined entirely by the integrator. While most commercial growers work with breeds chosen by their integrator, understanding the differences between available breeds helps growers manage their flocks more effectively and provides context for the performance data they see.
The global broiler market is dominated by a small number of primary breeding companies, with Cobb-Vantress and Aviagen supplying most of the world's broiler breeding stock. These companies offer several breed lines optimized for different production goals — and the differences between them matter at the farm level.
The Major Commercial Breeds
Cobb 500 is the most widely stocked broiler breed globally. It is known for excellent feed conversion efficiency and good breast meat yield. The Cobb 500 reaches a target weight of approximately 4.5 pounds in 35 to 38 days under standard management conditions. It performs well across a wide range of climates and management systems, making it a reliable choice for growers worldwide.
Cobb 700 is a heavier sister line to the Cobb 500, designed for larger bird weights typical of further processing markets. It reaches target weights of 6 to 7 pounds and requires an additional 7 to 10 days of grow-out time compared to the Cobb 500. Feed conversion is slightly higher than the Cobb 500, but total meat yield per bird is significantly greater.
Ross 308 is one of the most popular breeds from the Aviagen stable. It is known for rapid growth rate and excellent feed conversion, achieving target weights of 4.5 pounds in 33 to 36 days. The Ross 308 has strong leg health and good livability across a range of environmental conditions.
Ross 708 is the larger sibling of the Ross 308, bred for heavier bird weights and higher breast meat yield. It is commonly used in markets that require whole birds or portion control products. Target weights of 6 to 7 pounds are achieved in 42 to 49 days. Feed conversion is slightly higher than the Ross 308, but total meat yield per bird is excellent.
Performance Comparison
When comparing breeds, growers should focus on the metrics that directly affect profitability. Feed conversion ratio is the most economically significant metric. The Cobb 500 and Ross 308 typically achieve FCRs of 1.45 to 1.55 at 4.5 pounds, while heavier breeds like the Cobb 700 and Ross 708 achieve FCRs of 1.65 to 1.80 at 6.5 to 7 pounds. The higher FCR of heavier breeds is offset by higher total meat yield per bird.
Growth rate affects house throughput and annual production capacity. Faster-growing breeds allow more flocks per year, increasing total annual pounds produced from the same house space. Slower-growing breeds produce fewer flocks per year but may earn premium prices in markets that reward specific quality attributes.
Livability varies between breeds and between lines within breeds. The Cobb 500 and Ross 308 generally show livability rates of 94 to 97 percent under good management. Heavier breeds may show slightly lower livability due to the increased metabolic demands of higher body weight.
Matching Breed to Market
The ideal breed for a given operation depends on the target market. The whole bird market rewards lower body weights and efficient feed conversion. Breeds like the Cobb 500 and Ross 308 are well suited to this market because they reach target weight quickly with excellent FCR.
The further processing market for cut-up and value-added products rewards higher breast meat yield. Breeds like the Cobb 700 and Ross 708 are preferred in this market despite higher FCR because total saleable meat yield per bird is higher. The premium for breast meat in the further processing market offsets the higher feed cost.
The specialty and free-range market demands slower growth rates and more active birds. Slower-growing breeds and heritage breeds are used in these systems, with grow-out periods of 56 to 81 days. Feed conversion is significantly higher in these systems, but the premium price for specialty products compensates.
Breed Susceptibility Differences
Different breeds have different susceptibility profiles for common broiler health problems. Cobb breeds show relatively higher susceptibility to ascites and sudden death syndrome but lower susceptibility to leg problems. Ross breeds show relatively higher susceptibility to leg problems and woody breast but lower susceptibility to metabolic disorders.
Growers who understand their breed's susceptibility profile can adjust management accordingly. Cobb flocks may benefit from more aggressive ventilation to support higher oxygen demand, while Ross flocks may benefit from lighting programs that encourage controlled activity levels to support leg health.
Genetic Trends
Broiler genetics continue to evolve. Primary breeding companies are investing heavily in genetic selection for improved feed efficiency, reduced environmental footprint, and better welfare outcomes including leg health and heart and lung function. The rate of genetic improvement in broilers is approximately 1 percent per year for growth rate and 0.5 percent per year for feed conversion.
Growers should expect that the breed they manage today will perform differently — and better — than the same breed five years ago. Management programs need to be updated to match the capabilities of current genetics rather than relying on programs developed for older strains.