Rating Newest Oldest. Best Answer: Black-capped Chickadee lay 6-8 eggs that hatch in approximately 12 days. Babies fledge (leave the nest) when they are about 16 days old. Carolina Chickadee usually lay 6 eggs that hatch in about 11-12 days. Babies fledge when they are about 13-17 days old.Boreal Chickadee lay 4-9 eggs that hatch in about 11-15 days.Babies fledge when they are about 18 days old. Baby birds are not flying right away when they fledge. They leave the nest several days before they can fly.abies fledge when they are about 13-17 days old. Boreal Chickadee lay 4-9 eggs that hatch in about 11-15 days. Babies fledge when they are about 18 days old. Baby birds are not flying right away when they fledge.