On my Bluebird Trail, I have 6 house; 3 occupied, five hatchlings each. I believe they are about 4-5 days from fledging. The male and female are making hourly flights at 4-5 minute intervals; then a pause for 20-30 minutes; then feed again for an hour. also, it is early enough in the spring for a 2nd brood; they will likely change houses. Carolina Chickadees used 2 of the 6 houses too.
Life and Wildlife along the Little Buffalo River 
Our nest of four just took their first flights today! Amazing to follow their development from egg to little flyer.
Your photos are amazing. Thanks for sharing.
Thank you very much; I enjoy it. Steve