Minecraft wiki entry for Egg_farming, associated text: When hatching large numbers of chickens, a good rule of thumb is that the chickens will need well over a real-time hour to replace the eggs used to hatch them. Nights skipped in a bed do not count toward this time, and the chunk(s) containing the chicken must remain loaded (that is, near a player or in the spawn chunks). This also assumes you are collecting all the eggs -- remember, loose items like eggs despawn after 5 minutes.