I didn't know a thing about raising chickens until about 4 years ago, I learned as I went. Didn't find this site until 1 1/2 yrs ago. I haven't lost a chicken to predators, but, I've been very lucky. We all must learn as we go, pick a tip here and there and try to do what we think is right. You've had a rough start, but, you'll get it. Tighten up your security and you'll be fine. Thanks for adopting those animals, takes a good person to do that... Good luck...
