What would cause a Yellow Labs paws to change from black to yellow and grow feather like pieces out of the pad?

She is 6 yrs old. I have done hours and hours of reseach on the web and cannot find anything. I have spent over $600 at the Vet's doing bloodwork etc... I was told She had Hypothyroid disease but then it turned out her levels were too high. Then She had to be weened off the medicine. Her pads are all almost yello now and growing feather like pieces. PLEASE HELP! Thank you Kindly!