I've been experimenting with making my own feed, but haven't found any fish meal locally so I'd love to hear if you find a source.
Fertrell makes some organic poultry supplements, including fish meal, but there are no dealers in New Mexico. I've asked them for the closest dealer who will ship here. If they ever answer, I'll post it here.
So far when I'm not using prepared chicken feed, I've found that making alfalfa meal or leafy cuttings of alfalfa hay available is a good balance to mixed grains and lots of weeds/greens and room to roam for bugs. I keep my compost bin in the chicken pen area so they get all the trimmings from the kitchen. My chickens love soaked/sprouted whole wheat and rolled oats. I've been adding chicken scratch to their ration, but that is mostly corn, milo and oats. I'm trying to get away from corn & soy in the feed. So far, there are not a lot of options at my local feed stores here in the south valley if you're trying to avoid soy/corn.
We're feeding our chickens weeds and kitchen scraps also, but they eat a TON and always beg for more. I feel like I cant keep up with them. Someone told me that the produce market up here puts out old veg in the early morning, but that you have to beat up women who show up to collect produce for prairie dogs just to get a small amount.
I also have our compost in the pen...Are you making your own scratch then? I need to explore my options more - I feel like my older hens would really benefit from a more thoughtful diet.