Hang in there.

I've been raising poultry for a while now, and have had many depressing and/or frustrating experiences...like losing most of my first free-ranging chicken flock to foxes and hawks...almost enough to make you want to throw in the towel. I didn't, though, and once I dusted myself off, I figured out how to keep my birds safe (aviary netting and fencing!). After the chicken losses, another fox picked off several of my Muscovy (who could fly), and left one so injured she died in my arms.

Since I didn't want to limit their range, I rehomed nearly all of the ducks. And I once had coccidia in a group of juvenile chicks that took out more than half of them, most within a day or two (even with Corid treatment) of seeing bloody droppings. It's gutting.
I think you'll find even when you fix one set of problems, say security issues, there will be
other problems - but it's important to remember how much you enjoy having your birds and that you're trying your best to keep them happy and healthy. Like
@Nicsbackyardchicks said, maintaining perspective will help you get through the tough times. Take care.