I have had 5 dead chickens in the past two weeks with all the same symptoms. They each had blood covering their bums and had an egg close by with blood as well, like they had died from laying the egg. The environment they were living in changed from enclosed to more of an open area. We also ran out of their normal feed so they were put on a different kind temporarily. Do you have any ideas on what could possibly be killing them? could it be a lack of something in their feed? Any input helps!