i have two 10 wk old pekin ducks. they have been swimming in my pool since they were 6 weeks old. They love it!! they get to free range about 2 hrs a day 4 days a week. they get the option of going in the pool if they decide. they have a kiddie pool in their dwelling as well, but it gets dirty fast, and they sure love to go under and explore the bottom and ruffle their feathers all over. i opened the pool early for them and they have been the ones who have predominantly swam in it. i don't keep it heavily chemicalled, and when i do add, i keep them out for few days.. so far they have been fine. and they don't really get in it as often or as long as you might think, when given the option to decide, they like to nest under a bush in the breeze or plummage thru the bushes as well. i do plan on using the pool myself and am aware that there are parasites carried by some birds in thier feces that will cause "swimmers itch", and they recommend you keep it heavily chlorinated. when i do that, when the summer is good and hot, then maybe i will look for them some kind of above ground kiddie of their own as a substitue.