For awhile now, Ry has been eating duck eggs, while allergic to chicken eggs. The proteins between the two types of eggs differ, & while you may react to one, you may not react to the other. It is something you may want to discuss with your medical provider.
Depending on the size of the egg, I'll sometimes use a duck egg one-for-one for a chicken egg, and sometimes replace two chicken eggs with one duck egg. It depends on what the recipe calls for, as well as how many eggs I'm putting in there.
Baking with duck eggs is a real treat. Baked goods taste better- they're fluffier and richer. As a main dish, I find the flavor to be a bit strong when scrambled or over-easy. However, in quiche or other baked dishes, they're great.
We have both chickens and ducks as pets, and we get brown eggs from our chickens and green and white eggs from our ducks. The size varies, often the green eggs are similar to chicken egg size, while the white eggs can be quite a bit larger.
We decided to get ducks when we discovered Ry could eat the eggs. We already had a few chickens, so it made sense to add to our flock. They're really messy, but really entertaining; it's been a lot of fun having them. Plus, the kids love it!
If you're in a similar position with a chicken allergy, talk to your medical provider to see what he/she thinks. Just a reminder, I'm not a medical professional, so I cannot offer advise as far as trying it or not trying it; see what your doctor says!