Without questioning philosophy-- why are you spending that much on organic feed?
If the chickens are free ranging you can bet they are picking up some "non-organics" on their own.
A responding poster is paying $25 for a 88# sack of organic feed. At that price organic feed is not much more expensive than the commercial non-organic feed I am using. Only $.004 per pound more expensive. I could and would give it a try at that price.
At $30 per 50#, that's 214% more expensive than what I am using, no way could I afford, or justify it.
Chickens don't know about being organic. All they understand is hungry!
As for amount of feed being used--
10 full grown chickens, 9 hens, 1 rooster, I feed a little less than 50# per month of 16% laying pellets, add an additional 10# or so, per month cracked corn given a few handfulls at a time. Plus all the kitchen discards.
The OP doesn't number the chickens they are feeding so I can make no direct comparisson, chicken to chicken, feed to feed.
I don't brood chicks in the big chicken enclosure. The "biddies" are keep in a brooder in the barn and then moved to a tractor at 4 weeks. Only when they attain adult chicken size, 5 months or so, do they go in with the big ones.