Sorry to hear the birds were hurt and killed. Here, with our high predator population, I'd not have a flock in just a few days. We watched the fox trot past the chicken area 2 days ago while the birds watched. We have a dedicated charger on our fence and it must have hit it. It never even glanced at the birds. Mine have never free ranged, it just never ends well for the birds.

Now the fox has found chicken dinner, it is probably supporting a family, and will be back. They can climb in addition to dig, so hopefully you can keep the birds safe.

I've invested too much $$ and effort into my flock to feed predators. They have plenty of room, and I provide extra space when weather allows. It's the best we can do for them here.