Mother hen sits over its egg for 21 days and hatch out its chicks. Do you know it reduces its metabolic needs by reducing its feed intake. It reduces its fecal excretion also during this period so as not to contaminate its eggs. Only once or twice in a day it excretes its fecal matter well away from its brood. Before start of laying its egg it starts searching the safe place for laying its eggs. After careful selection of safe place it starts laying. It prepares its bed by using the straw or sand for placing its eggs. It turns its egg almost 90 times per day from 1 to 18 days of incubation and subsequently it does it only for 8 to 10 times a day. For the first three days it seldom gets up from the eggs as it is the most critical period for growth of chicks. The temperature requirement reduces when the incubation reaches 18 days and hence it sits over the eggs for an hour or two then roams about and again broods over the eggs.
While Ducks have lost the brooding instinct. The duck eggs are incubated by chicken if included in the brood. Guinea fowls have very good brooding instinct. It selects the safest and secure nest for laying its eggs. It sits over its egg for 28 days and bring out its keets.