what really happens to an eagle in the molting stage Do they really loose all their feathers?

Answer 1

They do moult all of their feathers but not all at once. for example, on the tail a bird Will moult the two outer feathers and while the new one are growing they will drop the next two. Although we have had birds that have dropped entire tails all at once. But this is usually because they are in a pen and feel comfortable to do so, a wild bird would not do this.

Answer 2

They lose most of their outer feathers, but they have others.