I would back off on the spray. Is it a Permethrin spray or enzyme spray? Either way, do something else. Mixing some Epsom Salts in very warm water, and soaking the birds legs in it for at least 10 minutes should help. After drying the legs off, apply some triple antibiotic ointment without benzocaine. Massage it into the scales and skin of the bird. It would be best to keep the bird off dirt for enough time to absorb the ointment. Avoid getting it on feathers, if you can, since dust/dirt will cling to the oily feathers. Doing it at night is best, when the bird will spend the next 8 hours or so on a roost. Apply ointment every night until redness subsides. One of the drawbacks of feather legged breeds is everything clings to their leg feathers. Once the redness disappears, and you find regular treatment for scaly leg mites is necessary, I'd recommend Nu-stock or a sulfur salve ointment. Some people claim success with Vick's Vapo-Rub but have never used it.