Chickens lay eggs every day but they are unfertilised so will not produce any chicks even if the hen broods them UNLESS she has been mated with a cockeral. If this has happened then the eggs will be fertile and baby chicks will appear from the eggs when mummy chicken sits on the eggs.
That's the birds sorted now for the bees.....
Some Chickens will go broody whether the eggs are fertile or not. My bantam did but the Rhode Islands couldn't care less.