An extra-embryonic membrane enveloping the yolk; site of the first extra-embryonic blood circulation.
Related terms
Yolk
The female germ cell (ovum) material maintained in the center of the egg by the ...
Yolk colour
A consumer-oriented indicator of eggs; influenced by pigments present in the fee...
Yolk index
Ratio of yolk height to yolk width.
Young pullet, pullet chick
Sexed female chick from hatch to 5–8 weeks of age.