These are lesions found in a similar location to breast blisters (see Miscellaneous Conditions of Poultry: Breast Blisters in Poultry). They have a hard crust on the surface and a core of dead skin and granulomatous reaction extending into the subadjacent subcutis. Their etiology is not well defined but they are not due to the causes listed above for breast blisters. Rather, they may be chemical burns due to prolonged contact of poorly feathered skin with wet litter containing ammonia or toxins.
Last full review/revision March 2012 by Frederic J. Hoerr, DVM, PhD, DACVP, DACPV; Rocio Crespo, DVM, MSc, DVSc, DACPV; Billy M. Hargis, DVM, PhD, DACPV; Larry R. McDougald, PhD; Eric Gonder, DVM, MS, PhD, DACPV