We have 3 3-week old ducklings living in our guest bathroom tub, and the mess is unholy.
The bathtub is lined with a towel, and we have two gallon milk jug waterers in there, as well as a chick feeder. Thank god cleaning is easy, because it has to be done every day or the smell will knock you out.
We put the ducks in the other bathtub to swim for 20 minutes or so while we take out the dirty towel, take out the feeder and waterers, spray the tub clean with the tub spray nozzle, wash the feeder and waterers, dry the tub, put a fresh towel down, and then the refilled feeders and waterers.
I guess I have to be honest and say that the cleaning process itself doesn't take any time at all (maybe 10 minutes), but it is gross, and it DOES have to be done every day, without fail.
I can't imagine what it'd be like without the set up we've got for them, and even so, cannot WAIT to get them outside!