Sex change in the plumage of brown leghorn capons following the injection of certain synthetic æstrus-producing compounds

It has been shown (Cook, Dodds, Hewett, and Lawson, p. 272) that certain phenanthrene and dibenzanthracene compounds are capable of causing all the known phenomena of œstrus when injected into overiectomized rats and mice. In order to investigate the actions of the compounds in another species it was decided to study their effects upon injection into capons. Any possible result of these injections was looked for in the modifications and growth of the comb and in the plumage. At the outset it may be stated that up to the present no acceleration of comb growth has been obtained from these compounds, but very definite alternations in the plumage have resulted from their injection. Amongst others, Juhn and Gustavson (1930,a ) have shown that œstrone is injected in sufficient quantity into Brown Leghorn capons regenerating feathers are female in type. For this reason it is usual, when dealing with this substance, to remove a number of feathers from certain regions (e. g. wing, breast, and saddle) of the capons some time previous to the commencement of the injections. The sex differences in this breed are extremely well marked so that deviations in colour or structure from either sex type of feather during experimentation can be readily appreciated: in the female, all feathers, with the exception of the neck hackle, breast, and flight feathers, are rounded and of a brownish colur finely pencilled with black; the breast feathers are similiar in structure, but are salmon in colour. The male, on the other hand, is a more highly coloured bird; the red or orange saddle feathers are long, lanceolate, and deeply fringed, while those of the breast and wing bar are a solid black and unfringed, and approach more nearly in structure to the female type.