title: Triple-yolked eggs in domestic ducks: a rare occurrence.
abstract: Multiple-yolked avian eggs, and especially triple-yolked (TY) eggs, are rare. Over two years, 48,224 duck eggs (Anas platyrhynchos domesticus) were individually candled and seven (0.0145%) TY eggs were identified in a commercial breeding and incubation environment. When compared with double-yolked eggs (Salamon and Kent,2016) their mean weight, length, width and shape index did not differ, but their dimensions were greater than for single-yolked duck eggs. Yolk fertility in the TY eggs was low (33.33%), and this was attributed to smaller yolk size and early ovulation and/or follicle immaturity. By day 8 of incubation, fertile yolks were positioned next to the airspace. Egg 5 contained one fertile yolk, and the embryo developed to enter the airspace, was consuming all three yolks, but failed to hatch.
authors.affiliation: School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland Ballyrichard House, Arklow, Co. Wicklow, Ireland attila.salamon@ucdconnect.ie.
authors.forename: Attila
authors.initials: A
authors.lastname: Salamon
authors.affiliation: Ballyrichard House, Arklow, Co. Wicklow, Ireland.
authors.forename: John P
authors.initials: JP
authors.lastname: Kent
mesh_terms: D000818:Animals; D004372:Ducks / Q000196:embryology* / Q000502:physiology*; D004530:Egg Yolk; D005260:Female
keywords: duck; fertility; incubation; triple-yolked egg; yolk position