There are different types of chicken sheds. ones for meat have probably only been in the sheds for 40 days on average, lots of dust overhead, .We used to have a tank with left, right, up and down facing spray bars, off tractor pto. full soak with detergent, then rinse from top to bottom.
The sh*te is actually litter, and in well run sheds should be dry and dusty. once soaked it takes 4 guys about an hour to wash, floor is scraped out prior with skid steers.
If the sheds are free range egg poultry houses, the sh*te will have been there for just over a year, and broken eggs caked all over, plus all nooks and crannies will have Red Mite and you will have to put up with the feckers for days, even after showering, if it is this type of shed, tell the flat cap to feck off
Andrew