A Bird Crime Scene.?

i have about 80 parakeets in a very large avairy, they have sometimes eaten other dead birds.when this happens there is usually a few birds doing it but this sounds like a rat has gotten in the cage.I have lost birds this way before and once all that was left was a birds face.check for any opening as they dont need much of a hole to get in.In my case it was a tiny gap where the wire on the floor had come off the frame.I have always had rats around the cage so i always have rat baits under the cages.