I have one duck. She and my Marans rooster are inseparable. He roosts on a very low roost to accommodate his lady love. He is the only rooster in that pen so I know he could roost on the highest one if he wanted. The duck tries to roost next to him every night. She tries to curl her webbed feet around the rung but usually ends up resting her chest on it with her legs straddled on either side. When she was younger, she would cram herself into a nestbox with a broody hen. She does have other sleeping options. She can choose from nest boxes, a dog crate, the straw covered floor or the roost. During the day she and the rooster are always side by side. It's funny because she seems to be constantly nagging him. If he mounts one of the chicken hens, she becomes frantic and quacks in ear and pulls his neck feathers. When she gets in the pool, the rooster stands next to it and waits for her to get out. Once, when the water was low, he waded in but decided he didn't like it and got out.