I also think that the chick that got eaten was either dead or something wrong with it. Many animals will eat their babies if they are still born or they sense that something is wrong with them. Instinct, I suppose, to keep only the strongest alive, or to keep them from being found by predators. (Same reason live-bearing animals will eat their placenta after giving birth)
I generally don't mess with my broodies while they're hatching. I don't want to get them riled up, and possibly breaking eggs or killing newly hatched babies. (Would a hen eat a baby to "protect" it? I don't know, but it's a possibility - I've been told by friends that raise rabbits that they'll do that...)
I generally don't mess with my broodies while they're hatching. I don't want to get them riled up, and possibly breaking eggs or killing newly hatched babies. (Would a hen eat a baby to "protect" it? I don't know, but it's a possibility - I've been told by friends that raise rabbits that they'll do that...)