Chicken breeding involves managing a flock to produce fertile eggs that will develop into viable chicks. This endeavor requires understanding the biological mechanisms of reproduction and the careful management of the birds’ environment and nutrition. Successfully raising a new generation depends on preparing a healthy breeding flock, facilitating mating, controlling incubation, and providing proper post-hatch care.
Preparing the Breeding Flock
Successful reproduction begins long before mating, focusing instead on the conditioning and selection of the adult birds. Breeding stock selection should prioritize mature, healthy animals with desirable characteristics, as their genetics and physical condition directly influence the viability of the offspring. Older hens and roosters tend to produce more fertile eggs and robust chicks than very young birds.
Nutrition is important for the quality of sperm and eggs. Breeding birds require a specialized diet higher in protein, vitamins, and minerals than standard layer feed. Adequate nutrient levels support viable sperm production and ensure the hen deposits sufficient resources into the yolk and shell for the developing embryo.
Rooster-to-Hen Ratio
A correct rooster-to-hen ratio is important for maximizing fertility and maintaining hen welfare. For lighter breeds, one rooster can service eight to twelve hens effectively. Heavier breeds, being less active, may only cover four to seven hens. Too many males can lead to hen stress and injury, while too few results in unfertilized eggs.
Breeding birds also require a low-stress environment with ample space (three to four birds per square meter) and sufficient perching and nesting areas.
The Biological Mechanism of Mating
Chicken mating is a rapid physical event that facilitates the transfer of genetic material. The rooster mounts the hen, performing a balancing act known as “treading,” and briefly presses his cloaca against hers. This moment of contact is often referred to as the “cloacal kiss,” allowing for the transfer of sperm from the male’s reproductive tract to the female’s.
Unlike mammals, chickens do not possess a penis, making the cloacal contact the sole method of insemination. This quick process is highly efficient, as the hen’s reproductive tract is uniquely designed to store sperm for later use. Sperm storage tubules (SSTs) located at the uterovaginal junction can keep sperm viable for up to ten days following a single mating.
Because of this storage capability, a rooster does not need to mate daily for every egg laid to be fertile. When an egg yolk is released from the ovary, it descends through the oviduct, where it encounters the stored sperm and fertilization occurs. A fertilized egg is identified by the blastoderm—a small, donut-shaped spot on the yolk that has begun cell division—differentiating it from the unfertilized blastodisc.
From Fertilization to Hatching
Once laid, a fertile egg must be maintained under specific conditions to allow the embryo to develop over a period of 21 days. If eggs are not immediately placed into an incubator, they should be stored at approximately 55°F (13°C) and turned periodically to prevent the yolk from settling and sticking to the shell. Incubation can be achieved naturally by a broody hen or artificially using a mechanical incubator.
Artificial incubation requires precise control over temperature, humidity, and egg turning. The ideal temperature for a forced-air incubator is 99.5°F, while a still-air unit requires a slightly higher temperature, typically between 100°F and 101°F. Humidity levels are kept at 45 to 50 percent relative humidity for the first 17 days to manage the egg’s moisture loss.
Turning the eggs is necessary to prevent the developing embryo from adhering to the inner shell membrane. Eggs should be turned at least three times a day throughout the first 17 days of incubation. Candling involves holding a strong light up to the egg to observe internal development, allowing the breeder to check for a growing network of blood vessels and the developing chick.
On day 18, the incubation process enters the “lockdown” phase, and turning must cease. At this point, the humidity is significantly increased to a range of 65 to 70 percent. This higher moisture level softens the shell membrane, which helps the chick emerge from the shell. The chick will internally pip, breathing air from the air cell before externally pipping and finally zipping its way out of the shell around day 21.
Post-Hatch Brooding and Care
After a chick has fully hatched and dried, it must be moved to a controlled environment called a brooder. Newly hatched chicks are unable to regulate their own body temperature, necessitating a supplemental heat source, such as a heat lamp or heat plate. The temperature at chick level should start high, around 90 to 95°F (32 to 35°C), for the first week.
The temperature should then be gradually reduced by 5°F each week to acclimate the chicks to cooler conditions as they grow. Chick behavior is the best indicator of correct temperature; chicks huddling tightly are too cold, while those panting and moving to the edges of the brooder are too hot. A comfortable chick will be evenly dispersed throughout the brooder area.
Immediate access to clean water is necessary for hydration; some breeders offer warm water or water containing electrolytes for the first few hours. Once hydrated, the chicks are introduced to a high-protein starter feed, which provides the necessary energy and nutrients for rapid early growth. The brooder must be kept draft-free and clean to promote good health during the first vulnerable weeks of life.