I have housed chickens and ducks together but found out that ducks devour the food and can drain a 3.5 gallon waterer in less than 10 minutes, get this they don't DRINK it they THROW it all on the ground and make mud holes all over the run. I would house them separately but that was my experience.... keep us posted! (btw now my ducks are a few months old and are HUGE and are housed in an old dog cage thing)
And I use a bowl so the ducks can clean their noses as well as regular chicken waterers. Across the yard is a small shallow pond so I would think a kiddie pool is perfectly sufficient. Good luck 
