I put 6 of them under a broody hen that has been trying to steal eggs for the last week. She was in heaven! The rest are at a friends house. She has a commercial incubator and tons of experience hatching which I don't. I really want to give my eggs the best chance possible and that is not in my homemade incubator which I generally use for emergency. I would have preferred to buy day olds but I didn't want hatchery quality.