Acquired a new cockerel to keep the ladies company about a month ago. He was very good, keeping the hens under control and not too protective with us - all in all a nice healthy fella (the last one was greedy and attacked everything - he tasted nice though

It's been a beautiful day here today - and at 1pm I fed the chickens and the cockerel was fine.
At 3pm, the dog started barking at the coup and I saw the cockerel was dead (the dog was ouside...)
The body quite stiff so had been dead a while - I couldn't see any marks, injuries or blood - I had a good look but couldn't see anything.
Any ideas anyone?

Mick