I have 3 golden apple snails in a 10 gallon aquarium with my female betta and they poop a lot (to the point where I could see a lot of poop floating in the bucket the first time I did a water change after I got them). If I had it to do over again, I'd only have gotten 2. I was overfeeding too, though. I was giving them 2 algae wafers every night and I think 1 is plenty, broken into pieces so they don't have to crawl on top of each other to eat.
Also, don't panic if you see one floating--they do float when they're dead, but some just enjoy floating. They let the air out of their shells somehow when they want to get back down.
I was surprised at how fascinating my snails are. I love watching them slither around (especially at night when they're much more active).