Double yolkers

These are more common than most people realise. They occur when, for whatever reason, a second egg/yolk is released from the follicle before the previous one has been encased in shell. The record for the largest number of yolks in one shell is 9 (source). In rare cases, the first egg – shell and all – is encased by the shell of the second. It is most likely to occur when a pullet is first beginning to lay, or when a hen is either beginning a new laying season, or tailing off (preparatory to moulting). The tendency to lay double-yolked eggs is inherited, and has (largely) been bred out of the modern hybrid layers.

Our Double Yolkers (as of 18th August 2009)

Hen	Date	Weight	Number/Season
Ella	2/7/07	94 g	1/1 (pullet)
Venus	6/7/07	96 g	12/1 (pullet)
Venus	16/10/07	104 g	81/1 (pullet)
Cindy	18/2/08	50 g	3/1 (pullet)
Delilah	6/3/08	82 g	184/1 (pullet)
Princess	6/3/09	41 g	1/1 (pullet)
Princess	8/3/09	44 g	2/1 (pullet)
Sylvie	11/3/09	46 g	2/1 (pullet)
Princess	26/3/09	54 g	14/1 (pullet)