The Relation of the Preen Gland to Rickets in the Domestic Fowl

Abstract

AS Hou (1928) has pointed out in his review of the literature, the preen gland in birds has long been a subject of discussion; but, as yet, no specific indispensable function has been assigned to it. Hou, on the basis of his own work, concluded that the removal of the preen gland from adult birds caused a disturbance of the feather growth and an impairment of general health, while in young birds its removal caused rickets, in spite of normal feeding and sunshine treatment. One of the functions of this gland, as proposed by Hou, is the production of a secretion which the bird, during the act of preening, rubs over its feathers. Activation of some of the constituents of this material, during its exposure to the sun, leads to the formation of vitamin D. The vitamin is then taken in by the bird, via the mouth, at a subsequent . . .