It will work fine with the exception if you use different feeds for the ducks vs chicken. They will eventually go to water on their own as well. Chickens are neither racist nor breedist if thats a word. I do it with my hens every season. I have a a Silke who has taken it upon herself to brood...
In West Central WI our hens drag out the chicks at 2weeks. At night of course they sleep in her plummage. So figure to keep them about 75-80 at night. The will huddle for more heat, but won't get an opportunity to overheat. The big there ng during the day is keeping them dry. They will be just...