From looking at your pictures it appears that you might be using oak dowels or closet rods. The same issue as PVC or pine dowels. They are consistent in shape and size. The birds feet are always using the same surface area when perching. This can lead to the sores on their feet. IMO natural Perches of the proper diameter are best.

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Long time amazon parent/breeder and many rescue zons. We are breeding 2nd generation of our Yellow Nape ,Double Yellow Head, Panama ,Orange Wing Amazons and TAGs, also outdoor aviary with flock of Cockatiels. If you need help or advice please feel free to contact me,if i can't help maybe i can find someone who can.Capt and "Jake" the YN
Avatar is myself and "Juanita" 12/59 Guatemala CA
Rescues looking homes,Mumbles(DYH male)Echo (YNA male) Rockie(BFA male) Nitro (YNA male) Yeah, Echo found a home