Im new at hatching chickens...but I do know that most birds will refuse an egg if its bad...infertile, underdeveloped, stopped developing, etc. You keep putting it back and the will push it away. I know thats how it is with my cockatiels. They push away the bad egg(s) even if I push them back. They do sense it somehow. Im sure chickens are the same way. They sense no movement. I have also heard that bad eggs get cold very fast if mama leaves them vs a good egg that will stay warmer much longer. If she keeps pushing them away, put them in a bator and see what happens. Won't hurt... Good Luck!
