It's not a rat snake, and it didn't necessarily eat any eggs. The "lump" you see is a threat display. Ask Stephan-A. He correctly identified the snake (from South America, I believe).

But yeah! Rat snakes will definitely eat freshly laid eggs. I imagine garters would too, if the egg was the right size, and smelled right. If I ever offered them to a garter, I would offer them without shells though. maybe even slightly cooked to avoid respiratory issues. You know, just cooked enough so that they could swallow pieces of the soft parts. I wouldn't give them shells since garters really aren't egg eaters generally speaking. I would say to Steve, go for it. I see no way that slightly cooked egg whites can hurt a garter. Or their "normal" food mixed with some egg whites. I don't see how it can hurt them. Just make sure it's not so "gooey" that it ends up blocking their breathing while swallowing. We've all seen milk come out someone's nose. We wouldn't want egg white bubbles coming out of our garters' noses while they are eating, possibly obstructing their breathing now would we?