I feed my 5YO male (65#) Dr Gary's Large Breed. He gets 3/4 cup 3X a day topped with a tablespoon of cooked/drained ground turkey mixed with cooked shredded green beans & carrots, and bluberries.
My Bully develops the same type of thing typically in the fall though. I will from time to time soak is paws in Epsom Salt and warm water for 5 or 10 minutes. DO NOT let your bully drink the water.