In my bantam coop I have several brooding hens. So far they have hatched out two babies. However, in one corner of the coop three "moms" are tending the babies and a clutch of eggs. In other areas I have three others brooding. I was trying to let "nature" takes it course but in the last couple days I have found three separate eggs that were crushed with almost completely formed chicks dead inside. This is the first time I've let the hens brood out so I know they are inexperienced but why are they killing/crushing the chicks before the hatch out. Could they be doing this when the chicks pip/peep (?) or what. What should I do? Any advice is very much appreciated.