Yesterday we had 1 dead chicken. The vent was bloody so I thought maybe the other chickens got to her after she was dead. Today, I have 2 birds that did not come to the feed trough. When I checked them I noticed that it looked like the skin and flesh had been eaten away From the vent to the lower part of the breast. I don't see any bloody beaks. These 2 birds are still alive and just sitting onthe ground. So I don't see how the other birds could be pecking this area. I would not have been abel see the area if I had not picked them up. I put them under the heat lamp, but think I will need to put them down after lunch. There roost is only about 8 inches off the ground, just enough to get off the floor. I'm thinking maybe a Rat? Any ideas?