A good thought, but you wouldn't know for sure without further research.
Organic bonemeal and blood may be hard to source for fertilizer, might be cheaper and easier to use lime and minerals. Depends also on the soil in which the ingredients were grown, which amendments they would need. I know nothing about growing grain,
If it's all certified organic then the company might be able to tell you the fertilizer used?
I agree that vegan is a big selling point (I sell at a farmers market and it's one of the most common questions I hear), but don't know that vegan chicken food would be so hot. Plant based yes. Do supermarkets sell vegan raised eggs? If they do, then vegan chicken food seems like a possible marketing strategy.
You might be still ok Josh. Good luck!