Howdy from Texas!!
I think it is important to know what kind of predator you are dealing with:
1. Where are you located?
2. I would suggest laying some 1x2 welded wire or 18 gauge 1/2 inch wcloth on the ground like a skirt on the run about 2-4 feet away and hammer them down with some landscape staples of some sort (amazon good resource for them)
3. The last suggestion is a huge perimeter of permanet like JackE (member here) has to keep most things away, assuming you have power within 50 feet. I have chosen not to go that route as my Coop is aboutt 100 feet from the barn.
4. If you have the funds to go all out with this venture just get a LGD (pyranees suggested) and train him constantly with the poultry. I would recommend two of them if you go that route.
So basically you can put a ton of money in the coop doing everything you can to avoid losses (which will happen). Or just get some loyal dogs that will guard your chickens (with training) and anything else you may add to the homestead.