Multiple-yolked eggs from a parthenogenetic stock of chickens.
The frequency of double-yolked eggs in a parthenogenetic Dark Cornish line of chickens was increased in certain birds. A line was selected that had a higher frequency of parthenogenesis and double yolks than the High parthenogenetic group. Selection within the double-yolked line appeared to have reached its maximum. The amount of parthenogenesis was higher in the offspring groups with embryos in both single and double-yolked eggs. The number of eggs and yolks from birds that laid a large number of double-yolked eggs did not differ significantly from the number from birds that laid only a few double-yolked eggs. Many triple-yolked eggs were seen in this stock as well as one quadruple-yolked egg. High frequency, double-yolked egg layers laid the same number of eggs, therefore, multiple ovulations may be due to a hormone or enzyme effect.
D000818:Animals; D002645:Chickens / Q000502:physiology*; D004530:Egg Yolk; D005260:Female; D010060:Ovulation; D010312:Parthenogenesis; D012641:Selection, Genetic