Dwarf Eggs and the Timing of Ovulation in the Domestic Fowl

Abstract

THE production of eggs considerably smaller than the normal has been reported in various birds¹ and has been well documented for the domestic fowl². Such eggs have been described as “witch eggs”, “cock eggs”, “dwarf eggs” and “wind eggs”—the latter term also being applied to infertile eggs³. It was known as early as the seventeenth century³ that the yolks of such eggs were frequently absent, but that there was a central nucleus around which albumin was secreted. In an investigation of 236 dwarf eggs, Pearl and Curtis² reported that 35 per cent of all dwarf eggs were without a yolk, 55 per cent contained free yolk and 15 per cent had a complete yolk.