Hasler the Cat; I took in two kitties, full grown, about two weeks apart. My husband brought up in his arms, a fuzzy female. Two weeks later I noticed a kitty with a broken back leg. He'd hobble away when I tried to bend over to grab him. I couldn't sleep, I had to save this stubborn kitty...
I've seen mites do this kind of damage. I've also seen bedbugs do serious damage, kitty will chew and chew, till the little tummy is bleeding and scabs forming. The b.b. will bite in places where it is hard for a cat to scratch, so they bite and chew and draw blood. Check around ears, paws, and...