By definition it is insoluble, ie it does not dissolve, so the vast majority of it passes through the digestive tract. This would rule it out as a significant source of macro nutrients.
Could it be a source of micro nutrients? These are the chemicals listed on the back of any multivitamin bottle.
As a general principle micronutrients are better absorbed in organic form (attached to organic molecules, also known as food) than inorganic form (rocks)
Are your birds getting enough Molybdenum? I went down this track many years ago, it is the road to madness.



Give your birds a varied diet and they should get all the micronutrients they need.
Cheers
Brett