Also the Eagles are beings of demi-god like power that are second only to Gandalf's kind, if even them. The reason Gandalf cannot carry the One True Ring is that its effects are proportional to the carrier's power. Gandalf, being basically a step below the gods, absolutely should never be near the thing because he could probably destroy the world with it. The Eagles, being of very similar power to Gandalf, also should stay the fuck away from the Ring because they obliterate the world. The reason a Hobbit has to carry it is because Hobbits are the magical power equivalent of a 17 year old battery you found at the back of your grandma's junk drawer.