Why do hard boiled eggs smell so bad when raw eggs or eggs cooked any other way seem to have no odor at all?
WAG here but possibly byproducts are created during the heating of the egg. In a boiled egg these byproducts are trapped inside the shell (contributing to the smell), but are released when the egg is cooked outside the shell.
(from memory:)
No, it’s the sulphur from the white that gets liberated when the proteins denaturate. Instead they form hydrogen sulphide. They are also responsible for the green film you can get on the yolk if you keep the egg warm for too long. (The hydrogen sulphide migrates and comes in contact with the iron in the yolk, together thry form something green.)
For a complete analysis, read On Food and Cooking by Harold McGee
And, of course, they don’t stink much if you don’t cook them too long.