ANATOMY

Detailed explanation-1: -A hen does need a rooster to lay fertile eggs. What’s the process of making them fertile? Basically the same as for most other species: the male mates with the female. His sperm travel into the hen’s oviduct and, in the case of poultry, fertilise the yolk of any eggs laid within the next couple of weeks.

Detailed explanation-2: -Back to our original question: with amniotic eggs showing up roughly 340 million or so years ago, and the first chickens evolving at around 58 thousand years ago at the earliest, it’s a safe bet to say the egg came first. Eggs were around way before chickens even existed.

Detailed explanation-3: -Hens will lay eggs with or without a rooster. Without a rooster, your hens’ eggs are infertile, so won’t develop into chicks. If you do have a rooster, eggs need to be collected daily and kept in a cool place before being used so that they won’t develop into chicks.

Detailed explanation-4: -The next question is perhaps, “Why do chickens lay unfertilized eggs at all?” The reason is that the egg is mostly developed before being fertilized. The chicken cannot know in advance whether the egg will end up fertilized or not, so it just has to go ahead and grow the egg in the hopes that it will be fertilized.

Detailed explanation-5: -A rooster inseminates a hen with his sperm by jumping on her back, lowering his tail, and touching her cloaca with his. As we mentioned earlier, this is called the “cloacal kiss”. Inside his cloaca, is a small raised point called the papilla. The papilla is what passes the sperm.