Just saw this old tread get woken up again. lol
As I said in my post written 6 years ago (!), if there's enough chicken/poultry poop mixed into the shavings, there should be enough nitrogen to supply the microorganisms and the plants, without burning plant roots.
I've been top-dressing my garden with barn sweepings (a mix of shavings, grass hay and poultry manure) for decades now, and have never, never had a nitrogen deficiency in my soil. The plants grow lush and healthy. Perhaps the key point here is "top-dressing," meaning that it is being applied to the surface of the soil, not turned under or mixed into it. When you top-dress, it allows a gradual integration of the materials rather than giving the soil a sudden dose that would cause a spike in microorganism activity and possibly lead to a nitrogen deficiency due to all that microbial metabolism.
So, really, I'm using barn sweepings as a mulch that composts itself while also holding moisture into the soil and suppressing weeds. The shavings and hay buffer the plant roots from the heat of the mixed-in poop as it breaks down, and also keeps the poop loose and aerated so there are no bad odors.The whole thing ends up as rich, dark compost within months. It works really well, in my experience.