Look's like Abe and Mary Todd's chicks are practicing their flight plans, not just showing how pretty they are. Flapping their wings helps them build up their wing muscles. Before this they had been growing the feathers needed for flight, a process called fledging. It takes the chicks about 8 weeks to go from hatching to flight readiness. As they flap harder and harder, they start lifting into the air which is really fun to watch. (Source: Cornell Lab of Ornithology). This is an excellent example provided by Diane Dix Massa of the osprey family in her neighborhood.