So, i got 2 little Cochin bantam hens 4 days ago who are about a year and a half old. they lived with 2 roosters at their old home, and now one has laid and egg and is trying to hatch it. is there a chance it will be fertile? Should i leave it and see if it hatches or is their no chance it would be fertile? Right before i got her, she had just hatched 9 chicks, if that makes a difference. Also, how much should a hen sit on the egg? Are they usually on it all the time, or on and off? Thanks