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 relevant info: Feed - layer mash, table scraps, weeds from vegetable garden, windfall apples Run: 20x30 for 9 (now 6 ) birds. Lots of shade, automatic waterer. At night they roost in a large former garden shed. Vax: I don't know if they were vaxxed for Mareks. Am trying to find out Birds remaining: 2 4yo Red Rocks, 2 4yo Aracaunas, 2 2yo Red Sussex DH poisoned rats away from the run. Could the sick chickens have eaten a poisoned rat and this would be killing them, too?