Eggs are made from the inside out．That's how the hen gets everything into the shell（壳）！
Inside a hen's body，the yellow yolk（蛋黄）is made first． Next，the yolk slides into a special tube（管）inside the hen．There，clear liquid（液体）egg white（蛋清） is added．Farther down the tube，two thin pieces of skin，called membranes（薄膜），wrap around the white．A hard shell holds everything together！
Now the hen goes to her nesting（窝）place．Her muscles（肌肉）gently push the egg down the tube and out her body—usually small end first．
It takes a hen a little more than a day to make and lay an egg．As soon as that egg is laid，she takes a day off to rest．Even so，all that egg laying adds up：Hens can lay about 250 eggs a year！
（from Contact kids）
（Questions：What's made first inside a hen's body？How long does it take a hen to make and lay an egg？）
