Cats hair is coming off of her back legs like on her tendons

We were given that a cat about 7 months ago. She was found under a car by a paramedic and we took her in. She isn't really gaining weight quickly and is very skittish but also sleeps and plays with our 2 other cats, 2 dogs and even in my chest sometimes. I have just noticed that she is missing hair in strips down the back of her legs. They weren't like this before. Not seeking medical advice , just wondering if anyone else has seen this ?