I had some young birds feather pick one time. To me this looks like the bird died first and then another bird started to pull feathers. Often when this happens others will join in. It would not take very long to pull this many feathers. It just doesn't look like anything attempted to eat any...
This is really a darlin tractor. I see you took some time and care in building it. Just a thought...many use a hardware cloth apron around the bottom and out across the ground to stop digging predators, rats and snakes.
Hope you have no more problems.
Yes, but in a smaller run they may would hit the fencing. In a larger run, maybe not. I have a large run too. The OP has a tractor so much smaller space. I don't know what has happened here, just my thoughts. I can see it being a rat as well, but no marks on the birds other than 1 with...
If it happened during daylight, one or both of the surviving hens *could* have plucked the feathers???
Are your mom's birds in a very small run/tractor?
Different birds may react differently?? I don't know?
I'd love to know if she has anymore ideas. Bears are not plentiful in my area but...
I have seen my birds get scared and fly into the side of their enclosure. Totally freaked me out, thankfully no one was injured.
In your case the 2 females may have automatically ran inside the coop. The 2 boys may have stayed in the run and could have totally freaked out because they are...
One more thought....Do you let them out to free range any? Could they have got into something poisonous? mouse poison, a small bit of antifreeze on the ground where someone parks?
Could someone have slipped them something?
I'm sorry I do not have much more to help. One thing is for sure, if this was a predator, they often return. May be tonight, tomorrow or next week. So be careful with the other birds.
I have seen many types of predators day and night. Most are opportunistic. I don't think they care what the time of day is, just that they are hungry! ;)
If you have not disposed of the remains yet I would really reexamine the necks for very tiny punctures. Sometimes difficult to find. Weasels are very small and can get through or under very tiny spaces. A weasel could have done this and not been able to drag the bodies back out under your coop.