My little 9-week old Speckled Sussex cockerel died last night as the group was settling in for the night. I found him dead under the roost. No external injuries, no sign of violence. He was healthy and vigorous just hours before he died. I assume he was on the roost with the rest of the small group when he died and fell down. Could it have been a heart attack or stroke? Does anyone have experience with sudden mortality of seemingly healthy and striving birds?