Even though all of the duck eggs in the nest, called a clutch, hatch at the same time, the hen starts spending increasing amounts of time on the nest from the laying of the first egg. She arranges her body from the breast down over the area, adjusting a bare spot on her belly -- called a "brood patch" -- over each egg as it emerges. The brood patch contains an extra set of blood vessels that allows the blood in the hen's body to directly heat the eggs. She adjusts the temperature of the incubating eggs by moving the patch around the nest to warm each egg individually.
Read more : http://www.ehow.com/list_7513140_signs-duck-ready-lay-eggs.html
Read more : http://www.ehow.com/list_7513140_signs-duck-ready-lay-eggs.html
if you have ever picked a duck up off a nest u can literally feel the warmth from the patches.
