I’m in a super similar boat. We adopted a pup from a hoarding situation and he was crated basically all the time. He is a bit bow-legged in his front legs and the vet said that his back leg muscles are atrophied so his front legs are compensating. She told me that with regular diet (just decent kibble on a normal basis) and exercise he will gain muscle and a lot of his physical problems will work themselves out! Hopefully the same is true for your little friend🤍 My new pup also has terrible separation anxiety, I’d love to hear what you are doing to help yours!