I use local grains, milled locally as well. I use mash for my chickens, most folks prefer to use a pellet on BYC. If the protein level is sufficient for the needs of your flock, does it matter that much from which supplier it comes from. The national brands cost more, for ten pounds less in my area. The national brands seem to sit on the shelf longer than the local feed. Most folks in my area use the local feed, be it starter, grower, layer. Most or at least many bird keepers need to watch their budget.
The national feed is ok, and I have used it, the bags are pretty and it has a marketing push behind it, so that cost needs be added into the price. My local feed comes in brown sacks, no frills, just feed, and ten pounds more for less. Of course the local feed won't likely have a propriety ingredient, and all the national brands seem to have some top secret additive that makes it worth the cost. I guess it could be so.
Some folks do not know much about feed at all. So they just buy the most expensive, supposing it to be the best. I have seen many times myself, where you do get what you pay for, but I do not believe this to be one of them. The birds just want to be fed… I don't think they really care one way or another.
So you will need to balance for yourself what you want to feed, how much you wish to pay, and if you believe you are getting 'more' bang for your buck out of local or national brands. There is NO best feed, for everyone. There is just a best feed for you.
Best to you and your flock,
RJ