Hello, I've had 5 chickens attacked in their coop. They have holes bitten out of them between their wings. This holes are about 3 inches by 3 inches. So far 3 have died. I thought it was rats so I put poison down. Once the poison stopped being taken I assumed the rats were gone. I put my birds back into their large coop again but two days later it's happened again? Does anyone have any idea what it could be??