Feeding them is a good option because cats can be predators to chickens too (especially chicks), and they kill wildlife for sport so much that they have helped humans make species extinct before. Are you sure that a cat did not cause the death of the chicks?
I have not been following along with this, but I am so sorry! That is horrible. I would suggest baiting the predator with meat (not live chicks) and having a live trap set.