Bulldogs World

I had my girl on Zignauture Venison and she stopped chewing her paws after being on TOTW wild boar and paw chewing  (I got her from a rescue and they were feeding her crap also) but she was shedding like crazy on the zignature I switched her to TOTW pacific stream after several weeks she is now scooting, scratching, paw licking, getting up and running and stopping and looking at her rear.. but her coat looks awesome.. im at a loss I think this may be from the food, she was scooting on TOTW wild boar too and not on the zignature but on zignature shedding by the handful.. I am at a loss.. any suggestions?  I dont see any fleas, she is on flea preventative, I dont ever see any worms either.. when I got her and she was scooting the vet said her anal glands were empty..she did just have hip surgery and just started using her legs again but I dont think that would make her itch and chew her paws.. arg.. help...