RIR bloody Rear and Eggs

[smcmanus]

8 months old Rhode Island Red hens. I lost one yesterday with a bloody butt that the other birds ate into. I also have another with same problem in the ICU on tetracycline. Now, this morning I found 1 bloody egg and was able to find the hen with the bloody butt before her friends ate her. I got her out of the coop and into the yard, and her vent looks normal except for the blood.

This same batch had cocci at age 1 month and I lost about half/25 birds before the Corid kicked in. So what should I be looking at? It seems that only those 3 hens are affected, so far.

Thanks
Steve