2 hens dead, third exhibiting similar symptoms -- please help!

Hello,

I share the care of a flock of 10 hens (mixed breeds & ages) in urban Philadelphia. Last weekend the other caretakers found two hens lying sprawled out, one inside the coop, the other outside in the run. Both were about 3 years old. Both died within 30-40 minutes of being found. No visible wounds or trauma, no known poisons or unusual foods ingested, but of course we can't be 100% sure about that. The caretakers had noticed that at least one hen was looking a little under the weather for several days. Now, for the past 5-7 days, another hen, also about 3 years, has been seeming a little lackluster; she stands still with her eyes closed sometimes, her comb is a little droopy (one of the hens that died last weekend also had a very droopy comb). Still seems to be eating and pooping normally, but it's hard to tell as we're not observing them 24/7. Again, no visible signs of trauma. I'm worried this is something catching. We've also noticed that most of the hens don't seem to be laying much in the past week or so, especially the older ones -- seems like it could be connected.

Chickens are bedded on straw inside the coop, and have an outdoor run that is woodchips/dirt (mud with all the rain we've been having). I did recently introduce three new, younger hens to the flock, after a couple days keeping them apart. New ones seem healthy, and came from a reliable person.

Thanks for any help you can provide!

 

We've actually had cool, extremely rainy and wet conditions for the past couple weeks, so I think I can rule out heatstroke. Didn't see any discharge, but I noticed today a couple of the other birds are sneezing -- bronchitis, or something else respiratory? All hens still seem to be eating and drinking. Are mites and lice easier to see at night with a flashlight? Just sort of comb through their feathers and shine the light and see what we see?

Thanks for the reply.