In the last two weeks, we have lost two very healthy two year old hens (Buff Orphington, Ameuricana) on separate days. Each of hens were walking around fine and normal in the morning, but by evening time they were very lethargic and visibly having trouble breathing, especially the first hen we lost (I didn't see the death of the second hen as it was in the middle of the night last night, but we aided in the death of the first to end her suffering. Her comb was turning purple and she was obviously suffocating). There wasn't any mucus or fluid from their eyes or beaks and no other outward symptoms other than not breathing well. The first hen did have some leakage of a yellowish colored fluid from her vent, but when we did a necropsy there wasn't a broken egg inside like I initially suspected; in fact, she didn't have any egg at all and wouldn't have laid that day anyway. The first hen we thought the neighbor's dog attacked her and collapsed a lung. The neighbor admitted that when his [adult] son lets his dog out and the chickens are around, it will run after them and bounce on top of them. (We all rent the same property, just different houses. Our chickens were here before their dogs were). But now with the second healthy hen having perished, I'm not so sure. Plus it coincides with the migration of other birds to our area, such as the wild Mallards to our creek (our pet Mallards aren't so happy about that, lol). Both hens were family pets, very healthy, great plumage, good appetites in the days before their death, fed scratch and layer crumbles, free-ranged on three acres of grass and locked in a coup at night for their safety. I've never had anything such as this happen in my twenty-one years of owning chickens, and I hesitate to replace them in my flock in case this is going to be an epidemic. Does this sound like some sort of bird flu? I was hoping that you more experienced and knowledgeable people might have an idea of what could be going on and what I should do about it. Is there someone I should contact to have them take the bird for testing? Animal Control in our area is pretty much worthless when it comes to taking and testing animals; they wanted to charge $150 for taking a skunk we killed that we thought might be rabid (it was super aggressive and not leaving our house). Anyway, any help is greatly appreciated!