My little Henny Penny sat on a clutch of brown eggs, not hers, she lays a small white egg. She got off after 23 days, without hatching. I collected the eggs and they floated, so I opened them, out of curiosity. There were formed chicks inside. These brown eggs are very hard to crack, and the skin is tough. I notice this when I am using them. Could this be why they won't hatch? This is the second time this has happened. It is so disappointing!