Hi everyone.
So my wallet is a few hundred dollars lighter, but preliminary assessments are looking good. General blood test is showing up with no abnormalities, save for a slightly high concentration of protein. There is a possibility that he has Chlamydia according to another test they ran, which may require treatment. Still waiting for the result for PBFD, but the vet thinks it is extremely unlikely, based on her inspection. She thinks Peanut may have anxiety, and that the feather abnormalities are most likely the result of his own preening. She says his feather are growing, but that they are subsequently damaged.
If PBFD test is negative, she recommended running a test under which he will be anaesthetised, to check for skin conditions. The test is extremely expensive though, almost as much as the sum of all the tests and the fee for the consultation. This is putting me off, given that she has essentially ruled it out as a possibility.
However, the visit has really put me at ease. The high probability that this is behavioural is extremely relieving.