This is a test of commonsense. Complete the next sentence:

How to spot signs of illness in parrotlets
Check the quality of the feathers.
Ruffled, thin, patchy, or dull feathers can be a sign that there is something wrong. A disease or parasite may cause the feathers to fall out or the bird may be plucking them from stress.
If they live alone and pluck their feathers, they may be lonely, not sick! You should still take your parrotlet to the vet, but consider getting them a companion. Examine their skin for swelling or lesions.