Depends on those grains and supplements being fed. Nutritional yeast is 39% protein!BOSS is 26.3...so depending on how much you are feeding of these types of whole grains.
When supplementing with both, you are essentially, boosting your 16% layer ration to 81% at any given time. This is pretty bad mojo for tiny chicken kidneys.
If feeding 18% layer and the fermented feed increases the utilization of that layer protein, you may actually be getting a good part of the actual 18% you are feeding. What the FF does is increase the absorption and availability of the proteins you are feeding, not necessarily increasing the actual total protein that is fed. When not using the fermentation on the same feed, a goodly portion of your 18% is being expelled onto the coop floor because it didn't get broken down well enough to be digested and utilized by the bird.
This makes sense . (had read on the OT thread that I should up the protein for FF or lots of oats or scratch) Thnx,BK.