Cytologic, Histologic, and Microbiologic Characterization of the Feather Pulp and Follicles of Feather-picking Psittacine Birds: A Preliminary Study

This prospective, blinded study was undertaken to determine if inflammatory changes of the skin, feather pulp, and feather follicles are present in feather-picking birds. Eight feather-picking or feather-mutilating psittacine birds and 4 non-feather-picking (control) psittacine birds were evaluated. From affected birds, we plucked 2 feathers each from a picked and a nonpicked area. Feather pulp was expressed for cytologic examination from 1 feather each from an affected and a nonaffected area and pulp from the other 2 feathers was expressed for bacterial and fungal cultures. In addition, a feather follicle from each site was excised for histologic examination. From control birds, we plucked 2 feathers from the same regions as from affected birds and performed the same examinations on feathers and follicles as for affected birds. Cytologic examination of feather pulp from both feather-picked and control birds revealed no bacterial or fungal organisms. Histologic examination revealed no inflammatory cells in samples from either feather-picked or control birds except for 1 sample from a nonpicked area of a feather-picking bird. Only 1 pulp sample from an affected bird and 1 sample from a control bird grew bacteria. These results suggest that dermatitis and folliculitis should be considered unlikely causes for feather picking or mutilation unless confirmed by cytology, biopsy, and feather pulp culture.