In winter: they have a 10 by 6' pen in the basement. Daily chores: collect eggs, remove one forkfull* of damp straw, sprinkle one or two flakes of fresh straw on top of existing straw, sprinkle fresh sawdust pellets on top of sawdust pellets in splash catcher.
Once a week or so - remove a few forkfulls of damp straw around edges of where the daily forkfull comes from, replace with two flakes of fresh straw, replace sawdust in splash catcher with all fresh.
Once a month or so - remove all used straw and replace with fresh. I would not do this except I want to keep an eye on the flooring underneath, which, so far, has been just fine. Next winter, will likely only clean out a couple of times.
I asked my beloved, and visiting neighbors and friends what it smells like. Their answers: a little like fresh soil, like straw, so little aroma that it doesn't really smell like anything, certainly nothing bad.
In late spring, summer, fall: Daily chores: collect eggs, replace water in drinking and swimming pans, check straw layer in shelter. Push straw aside, stir shavings underneath with a four foot long 1 inch by 1 inch stick. Pull straw back over top. If needed, pull straw layer (about two or three inches) out of shelter, stir shavings, add three flakes of fresh straw.
I have ten runner ducks. As I mention regularly, for me, finding a way to manage the water made a tremendous difference. While they were young (three months and under), I needed to clean the brooder three to five times daily - and they lived in the house all that time and the house, and the room they were in, did not have a bad odor.
*I use a pitchfork.