wind egg
wind-egg

The male midwife toad (Alytes obstetricans) winds egg strings round his thighs and carries the eggs around for up to eight weeks.

In a mature hen, a wind egg is unlikely, but can occur if a bit of reproductive tissue breaks away, stimulating the egg-producing glands to treat it as a yolk and wrap it in albumen, membranes and a shell as it travels through the egg tube.