I've read many forum discussion posts on this website in the past, but this is my first posting. We have had a few strange incidents over the past few weeks, with today's really stumping me. I'm hoping to get some insight into what might have happened.
First, for a little background info, I live in urban central Ohio with 6 hens in the backyard. They were raised together from day 1 (they will be two years old in April) and the pecking order was pretty well established -- until this past summer, right before their first molt. The smallest bird, Belle, started getting picked on, and nearly died multiple times due to injuries to the back of her head inflicted by the other hens. She managed to stick around without any particularly severe lingering health issues, and the two highest ranking girls never had a problem with her, so we kept the three of them together and kept the three bullies together (I know that separating the flock is never a good idea, but we had tried re-assimilating her many times with no luck, and she otherwise seemed fine (no obvious sign of illness)). Over the next few months, though, it was clear that Belle had become blind as her eyes were now light blue/gray, and she was quite timid and less vocal than before. But, otherwise, she was eating, laying eggs, and exhibiting nearly normal pecking behavior.
Anyway, fast-forward to today: the hens are particularly loud all day, so my roommate goes out to check on them. Two of the hens have escaped the fenced-in backyard and are wandering around in the neighbor's yard. One hen is hiding on the floor of the coop cowering, and Belle is in the fenced off run (roughly 20-30 square feet, separate from the rest of the backyard) dead, having clearly been attacked. Feathers are strewn about, and my roommate describes the scene as her having had her spine/back ripped out.
The weirdest part? There is a GIANT dead rat in the middle of the backyard with blood around its mouth and nose. It doesn't appear to have any wounds, and only has slightly mangled fur. There was a small amount of rat poison underneath the coop floorboards (in a place that quite literally no chicken, dog, or cat could get to) because of a rat infestation we had last winter. However, I read that a poisoned rat typically will be too weak to leave its home or nest as it dies.
So, did the rat kill my chicken? If so, why did it immediately die afterward -- with no apparent wounds on it? The rat's eye appears to be calcified or hardened in some way -- was the rat sick with some other disease?
Side note: one of our other apparently healthy, mid-ranking hens became very sick very suddenly about two weeks ago. One morning, she would not stand up or get out of the coop at all. I brought her inside, thinking that she may be egg-bound, as her tail was down all day and she hadn't laid for a little while (none of them have been too productive ever since their first molt this fall). I relaxed her by soaking her bottom half for 20 minutes at a time in a warm water bath and trying to lubricate her vent with vegetable oil. I gave her a calcium supplement, and tried to feed and water her. Otherwise, I left her in a dark, quiet place with a heat lamp over her covered cage. Overnight, she quit eating, quit drinking, was no longer able to stand at all, and had labored breathing. At this point, it was clear that she was not egg-bound, but that she had severe diarrhea and must have been losing weight for awhile before exhibiting any symptoms (she had kept her feathers fluffed out to ward off any suspicions from the flock). Her keel bone was exceptionally protruded and her feathers were all gone down her keel bone to her vent. By the next morning, she was keeping her head down and leaking a mucous from her beak. I had her euthanized that afternoon. My fear is that either Belle gave her this illness, or she was contagious and infected the other hens. Could this have anything to do with Belle's attack today?
I'm sorry for the huge post -- I'm just so upset and confused by the whole experience. So many incidents in so little time. Thanks.