This has happened to me 2 times with broodies, first time was a staggered hatch shared between two broody hens, once the first baby hatched the one hen tried to protect it while the other ripped it to shreds. Second time was just recently when 3 hens decided to go broody almost the same time. I put 10 eggs under one hen and 5 eggs under another due to hatch within days of each other. The one with 10 eggs hatched all her chicks (baby seramas) and did really well with them, 2 days later one of the chicks under the hen with 5 eggs hatched so i took that chick which was a cochin baby and put it in with the other hen, at the time she took it right in and kept it warm under her, the next morning the chick was shredded. out of the 5 eggs under one broody only 2 eggs made it to full term uncluding the chick that was killed. I kept the lone cochin baby with its mama and left the other one to raise her 10. Lesson learned!