Is the stipulation valid if eggs are specified for a hen?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
The opinion that stipulating eggs for a hen is invalid exists because there is no certain measure known by religious law. However, the preferred view is that it is valid because it is ascertainable by custom, analogous to stipulating a sheep as a milker.