Hen spending a lot of time in nest box- is she getting ready to lay?

[Tanichca]

My six-month-old mallard/call/something hen is spending most of her days in her big nestbox, moving hay around, shedding a few feathers, and not going into her water as much as her drake. Are ducks like chickens in that when a hen is ready to lay, she hangs out in a nestbox? Thanks in advance!