Try the deep litter system - the mess is continually turned over by the chooks and breaks down naturallyHowdy Megacakes
Is the shed just going to be for sleeping, nesting and sheltering from the weather? Will they have an outside run for during the day?
Many, many years ago I had 6 LF's whose roost and nesting box were in the garden shed. They free-ranged the garden all day and only went back to the shed to roost or lay. I was vigilant with keeping it clean and the only 'messy' spot was under the roost. I honestly never had a problem with smell. They shared the shed with some garden tools and other bits and pieces and this was never a problem. I used to let them out every morning and once they had gone to bed, just shut the shed door for their overnight safety.
from biological action. shovel it out once a year for your garden.
xxxx M