I just noticed that you said SOME of your eggs stink. Since it's only some of them, not all of them, I'd think a weed was the culprit since only some of your hens are eating it.
Check your property for garlic mustard. Also, ramps or other forms of wild onion/ wild chives. I dont' think chickens are stupid enough to eat skunk cabbage, but that would do it, too.