After losing nearly 2 dozen hens from a fox attack a few years ago I was reluctant to get new birds again. The attack happened in a span of 15 minutes. I went into the house for a moment (15 minutes) and when I came back out the flock was decimated. I know for a fact is was a fox as I saw the culprit running away from me through my pasture and into the neighboring field.
Therefore, this time around I purchased and electric net fence and also have a large house inside the fence to put them in at night to protect them from owls. The net fences can be moved around easily to new areas for grazing and scratching. It was a great solution since I also have coyotes and raccoons in the area also. So far it is working beautifully. I purchased mine from Kencove Farm Fence Supplies. But it is pricey and you may need additional equipment to provide the power to the fence which will add more cost. So...
If you don't go with an electric fence then a fenced area that has wire on top works well too. You will also want to bury the wire along the fence a foot or more into the ground so that dogs and foxes cannot dig their way into the coop.
As far as cats, You will want to make sure that they (cats) cannot get to the birds while they are young - can't stress this enough. Once the birds become full grown the cats don't seem to have any interest in them and rather go for easier (smaller) prey. I have always had cats with chickens but take extra precautions when the birds are young.
