I don't know about Edgewood. I would call around to the feed stores near you. However....
DE you can get in smallish (but maybe they're 10#) bags at La Montanita Coop. DE would be tough to do in bulk/small packages b/c it is so powdery.
Grit you shouldn't need, just get a bucketful of dirt from outside and put it in a bowl, the chicks will peck out what they need. If your chicks are already outside, then you shouldn't have to worry.
Oyster shell you may not need depending on the quality of your hens' diet. But you may have a fellow chicken keeper nearby who will sell you a pound. I could sell you a pound of oyster shell as well as various supplements I buy for my chickens (kelp, diamond yeast probiotic) but I'm in the south valley. Not so close.
I know there are some other chicken keepers in Edgewood on this list, so hopefully they will chime in with sources closer to you.
Good luck! Jen
Thanks Jaime. I have gone there and gotten some of my supplies. Will check them out again. I agree, they are really nice.