The other morning we found one of our hens with no head, and 2 very distressed cockerels.
One cockerel never moved (although there was no obvious injury) and died the next day. The other cockerel wandered around looking lost for a few days and then died overnight.
Currently we suspect the Stoat that has been around the garden. A few days before the chickens were attacked, we watched him rolling a dead rabbit up the hill, like it was a log. No signs of injury to the rabbit either - how do they do it?