We have a rabbit and a guinea pig and in the rabbits cage was one of those little hammock things, well the rabbit got it's back foot caught in the hammock and it looked okay after we got it's foot out, but a few days later it had swollen huge and all the fur had fallen out and it was yellow and purple and covered in pus. Needless to say we took it to the vet right away and he said that it probably wouldn't make it and would we like to put it down, we said no. So the rabbit spent three days at the vets, then came home and went through 7 months of us washing and cleaning and wrapping it twice a day every day. The rabbit survived but lost all the toes on that foot, he can still hop on it and everything, but if you have a hammock in your cage, my advice is to take it down, fold it in half and sew up the sides to make a cozy.