Today I had all my chickens locked up in their run (often I free range if I’m home) and I was letting the littles (4 week olds) run around with the rest of my flock. I went inside for 1 hour maybe 2 hours, and when I come back out to check on the chicks, my silkie rooster was dead in the middle of the run! When I flipped him over to check for injuries a small amount of brown liquid came out of his mouth. He had no injuries, and all the hens seemed fine and normal. I let all the hens out to free range and put the chicks back in their outdoor brooder. He was young, only a year old, and seemed healthy earlier this morning. Any thoughts on what could have caused this?