Rooster suddenly no longer aggressive and passes away

[stephensc7146]

I had a bantam rooster, who was a little on the fiesty side start acting funny about a week ago. He no longer attacked anyone who went out to feed/water the flock. just calmly walked around and ate/drank when food and water was placed into the run. this morning my brother found him dead. Anyone know of anything that could cause this?? He came from tractor supply so i'm not sure if he had any vaccinations before being shipped to the store, and he was a year old upon passing away.
I'm hoping it was nothing contageous, because he shared a coop with 5 other hens.. and I would hate to lose the rest of them too.
Any feedback is appreciated.

 

[macdoogle2]

No idea, but I recently lost 2 hens from 2 different coops. Nothing appeared wrong with them. Just found them dead in the run. The rest of the flock was fine. Sometimes chickens just die.