Three things are accomplished by turning of eggs during incubation. 1. The variety of various nutrients within the egg are made available to the embryo (chick). 2. The wasteproducts produced by the embryo are distributed within the egg so as not to become concentrated and thus toxic. 3. The chick as it grows is not as likely to become stuck to the interior of the egg shell and not be able to accomplish a final turning to cut out of his shell with his beak during hatching. The brooder hen sees that the eggs are turned under her. In an incubator turning must be done mechanically or by hand several times a day.