I guess it depends on who you ask. In the “old” days they use to feed raw eggs to their dog for their coat. Nowadays there are many products on the market that can do that and you can be safe adding it to their food. I give Grizzly Salmon Oil to my Doxie for her coat. Personally I would never feed my Doxie or any dog for that matter a raw egg, due to salmonella and other bacteria that may be in the egg. If you want to feed an egg, I would scramble it and only feed in moderation. Maybe once or twice a week.
Here’s a couple of links for “Bad Foods for your Dog”. It advises eggs are bad, not only for salmonella but raw egg whites bind to the biotin that a dog ingests and prevents it from being absorbed.