Incubating 6 Copper Marans Eggs Under Broody Chicken

On February 26, 2015, we put six black copper marans eggs under a broody chicken. The chicken incubation period is 21 days, assuming everything is controlled well as far as temperature. If there are cold periods, the date could be extended by as many as three additional days. 

The weather here has been pretty cold at night. On the very cold nights, we use a lamp in the coop to keep it warmer. 

I created a poultry hatch date calculation table with Google Spreadsheets. So far, we just have the chicken dates. Once we find the guinea eggs we will add formulas for that column. To use the table, just copy over the "Date Started" cell under chicken and the formula will calculate your expected hatch date.