After I started raising chickens for eggs I realized just how much that I didn’t know about chickens and sex. Now, I can talk and write about sex with a man all day long, but when it came to my hens I was completely ignorant. So then when I told other people that I had chickens, they would ask me about sex, eggs, and roosters and so on. I had to do some research to get answers for others and myself as well. I hope that this short blog can answer some of your questions.
Mating of chickens, if you have never seen it happen, can best be described as "just like cats." The rooster mounts the hen–who must "stoop" to take his weight. He holds her by the feathers on her neck just behind the head. The sex organs are very like other animals, but kept inside except for the very short duration of mating. Roosters do not have penises. If you’ve seen one chicken butt, you’ve seen them all. The difference is on the inside. Both male and female chickens have one exterior opening called a cloaca. When a rooster mounts a hen, he will tuck his tail under her’s in what is romantically called the "cloacal kiss" passing sperm to fertilize the egg (before the shell goes on!)
The sperm travels up the oviduct, where an egg is released every day or so, and one mating can leave enough sperm to fertilize each egg for up to a week. The egg travels back down, where it receives the egg-white and the various membranes, and then last of all, the shell is deposited shortly before the hen lays her egg. Each egg takes a little more than 24 hours from the release of mature ova to laying the egg, with most of that time being the last part–the formation of the "white", the membranes and shell. So each hen will lay her egg a little later each day until she skips overnight and resumes laying early in the morning again. Also, did you know that the egg is soft until it hits the air, and then it will calcify or harden?
Roosters can mate with females as often as they like, because roosters can control how much sperm they expend during a sexual encounter, allowing them to use more or less depending on social and environmental factors. Two important factors are the competition—whether other roosters are mating with the same hen—and whether a rooster has already mated with a particular hen. Roosters distribute their sperm resources strategically according to several factors, including the reproductive value of the female. Roosters judge a female’s reproductive value by the size of her comb. Hens with large combs tend to produce large eggs and lots of them. Fertilizing these eggs is like hitting the jackpot. A rooster’s social status influences his allocation of sperm. When a dominant rooster faces competition from other males, he will expend a lot of sperm and progressively increase the number of sperm. This is like buying more tickets to increase one’s chances of winning the lottery.
If you are going to have a rooster then I would suggest a quantity of one. Farmers have always known that over time roosters grow less interested in mating repeatedly with same hen. Hens also grow bored with mating the same male. By counting semen, the researchers discovered that roosters also reduce the sperm progressively as they continue to mate with the same female. But when a new female is introduced, the rooster wants to copulate and secretes more sperm to his new mate. Hens are not large enough to fight off a sexual advance, but they are able to squirt semen back on a rooster after copulating, which lasts about a second. by Peaches Jones