Dudes. Our chickens are dying. Found a dead one this morning. They were fine when they went to bed . This is #3. Is there a virus/ illness that will kill them like this? The one bird I saw before she died was lethargic and water came out of her mouth when I petted her on the head. DH says this suggests crop stasis but why would it be passing successively to each chicken? The first two were 4yo Red Rocks. The one this morning was a 2yo Red Sussex. What could this be? Possibly pertinent info: Feed: Layer mash, table scraps, weeds pulled from garden, windfall apples... Large run (easily 20 ft x 30 ft) with plenty of shade. Moderate temps right now - 70s. We had 9 birds last week and are now down to 6. I don't know if they were vaccinated for Mareks. The farm we got them from is very serious about backyard chickens (they run a class DH took) so I'm inclined to think they had the vax? I'll check with DH. We do have rats which DH poisons away from the run. Could they have eaten a poisoned rat and this is making them sick? TIA for any advice/mystery solving.