Is it dominance or experience that wins the day? When it comes to mating success and fertility in chickens, the answer might be surprising.
Broiler breeder fertility has been declining over the past decade, raising concerns about both productivity and the long-term sustainability of the industry. At the 2025 Poultry Science Association annual meeting, Marcela Quino, a graduate student at Auburn University, presented her research examining how time of day, rooster competition and behavior influence mating success and fertility during the early production period.
“Hatchability, fertility, chick viability and production efficiency have been declining,” she said. Past research focused on physical and physiological traits such as rooster body condition, sperm quality and body weight. Quino’s research examined behavior.
“One of our study objectives was to identify daily patterns in mating interactions and attempts and their evolution with age to evaluate mating behavior. We also sought to assess the relationship between fertility and mating attempts,” Quino explained.
Why behavior matters
According to Quino, mating behavior is influenced by several social and environmental factors. “It is believed that if a rooster is more dominant, it’s more likely to have more mating interactions,” she noted.
Courtship behavior also plays a role in whether hens accept a mating attempt. And male-male competition can increase aggression and disrupt successful copulation.
Another key factor is timing. Birds naturally regulate their activities to a 24-hour biological rhythm. However, the behavior of commercial broiler breeders is affected by lighting control.
“Knowing the timing of some behaviors is really important so that we can enhance the birds’ reproductive efficiency,” Quino said.
Study design
The study involved 472 broiler breeders, including 64 Ross 44 roosters and 480 Ross 308 hens. Roosters were placed into one of two treatments starting at 20 weeks of age:
- With competition: four roosters housed together with 36 hens (1:9 ratio)
- Without competition: single roosters housed with nine hens
Behavior was recorded during the early egg-production period at 25 and 30 weeks of age, with lighting from 7 a.m. to 9 p.m. and feeding at 8 a.m.
Mating attempts were classified as successful when cloacal contact was achieved and unsuccessful if cloacal contact was not visible. Fertility was measured weekly using egg breakout at day 3 of incubation.
Mating success
Quino found that roosters housed with other males had a high incidence of unsuccessful attempts, even as the total number of mating attempts increased. However, successful matings remained consistent regardless of competition.
Age also played a role. Younger roosters at 25 weeks showed more unsuccessful attempts than those at 30 weeks. Quino suggested this was because the younger males lacked experience and were simply habituating to the hens. Older, more sexually mature roosters showed “more expected strategies of courtship due to their experience,” she said.
Timing makes a difference
One of the more producer-relevant findings in Quino’s research was how mating behavior changed throughout the day. Her study revealed fewer mating attempts and lower success during midday and two clear peaks in mating activity: early morning and late evening.
“We had peak total mating interactions at 7 a.m. and 7 p.m.,” Quino said. However, success differed between those windows. Early morning showed higher mating activity but also more unsuccessful attempts. In contrast, the most effective period occurred in the evening. “We had a peak of successful attempts at 7 p.m. with fewer failures compared to the morning.”
Linking mating behavior to fertility
The study also examined how mating behavior translated into actual fertility. “We observed a moderate negative correlation between fertility and unsuccessful attempts and a moderate positive correlation between fertility and successful attempts,” Quino noted.
She also explained that reproductive success has both pre- and post-copulatory components. “With more cloacal contact, fertilization success was increased. When cloacal contact did not occur, we saw that the eggs were less fertile,” she said.
Practical takeaways
In conclusion, Quino emphasized that management decisions can influence mating success. “Although competition increased mating activity, it didn’t translate to more success.”
Timing, however, mattered greatly. “The late-evening period emerged as an important window for successful attempts, making it a potential focus for breeder management strategies.”
The results also indicate that experience matters. “The consistent success and declining lack of success of roosters with age suggests a potential role of experience and learning on mating interactions,” Quino said.
Looking ahead, she said that her future research will focus on hen receptiveness, courtship behaviors and how rooster interference affects mating outcomes.
For producers, Quino’s work revealed that when and how birds mate can be just as important as how they are fed or physically managed, and that small adjustments to the timing of light periods and the age of birds can increase fertility.
