I actually had an adult male call duck drown in his pool a couple of weeks ago. This is a pool he had been using for many months and he had no problems getting in and out. I got him from Dennis at Wapsi Waterfowl and he told me that it DOES happen that ducks can drown for no apparent reason. It was upsetting, to say the least, and I am concerned about his "wife". I am going to try to sell her to someone with a snowy male since I've decided to stick to geese and chickens and give up on ducks. (Big Sigh).