We have two pairs of nesting Carolina Chickadees in our backyard. We know exactly where their nests are because they are using two of the nest boxes we put out for them a month ago. These birds typically nest in tree cavities, so they easily take to using nest boxes.
Chickadees will lay around 3-10 eggs. Our two nesting pairs have laid 6 and 5 eggs. Both nests are the in stage of "sitting on the nest"also known as the incubation period. The eggs should hatch in 11-14 days. As you can see the nest looks fluffy and comfortable. They build their nest with twigs and moss, then line the nest with fur. I think there are a few of my dog Ella's hairs in their as well!
To learn more about chickadees see this site: all about birds
To learn more about nest boxes see this site: birdhouse network