Even though eggshells are very thin, the eggs are not crushed by the weight of the female bird when she sits on the nest to incubate them.
فمع ان قشرة البيضة رقيقة جدا ،‏ لا يكسرها ثِقْل الانثى عندما تجلس عليها لتحتضنها .‏