A neighbor saw something like a ferret

[Vocjuved]

Were the chicks also left headless or were they just gone?
A weasel is not gonna pick the bird to the bone. That sounds like a hawk who normally hunt in the mornings. They could also pick up chicks and take off with them.

I found no evidence of the chicks. I haven't seen hawks, but there is a nice pine tree in the neighbors yard that could easily have some. Three years ago many hawks were in the tree.

If it's hawks, what is a good deterrent, short of putting wire over the run?

 

[Vocjuved]

So sorry!
have your survivors locked in a safe coop, or somewhere safe, until this is resolved. Are they dying in the coop? When free ranging? In the run? Keep them safe while you reinforce your run, or coop, and no free ranging at least for a few weeks.
If you can set up a game camera or two, you can see who's visiting!
Hawks tend to visit and kill one, then return a couple or three days later, and get another. Having the flock on lockdown for two or three weeks can have that particular bird move elsewhere. You are having multiple deaths, so if there is a hawk, you have other critters visiting too.
Only trap if you will shoot the fox, raccoon, or weasel that you manage to get.
Mary

I did put them back into the run. I also am looking at possible weak areas in the wire and shoring up. I have had two die in the run, one on free range. But I have checked the perimeter of the run and shored it up. We intend to shoot the offender!

 

[Folly's place]

Don't shoot any raptors! They are all federally protected, so avoidance is the answer there. Otherwise, being very lucky to be there when a predator shows up is hard.
Mary