I've never hatched/incubated eggs but, I think you would be better off have two incubators- one for chicks, one for ducks. I would think ducks need different temps. & humidity levels than chicks require. As well as different brooders because ducks love to play and make a watery mess, chicks would be chilled and may get ill from such exposure. Ducks also grow much faster than chicks, even though they are about 28 days till hatch, and chickens about 21.