Why do hens lay eggs even without fertilization?

From an evolutionary point of view, it is wasteful to lay an egg every day without that egg developing into a chick. Eggs are very costly to produce, so you have the right idea there. read more

They just lay eggs and if the eggs are fertilized, some of them may survive and keep flock's numbers up. If the eggs aren't fertilized, they'll only be good for eating. From an evolutionary perspective (and from a common sense perspective), the hens just lay eggs and the broody ones sit on them. read more

In fact, some species don't need sperm at all! The development of the egg without fertilization by the sperm is called"parthenogenesis." Among animals that can develop without sperm are some fish, a species of lizard and even turkeys! But not chickens. They do need sperm to develop fully. read more