Nobody has been sick on my watch... and I'm pretty lazy...
Do not make the wild bird feed you sole ration or you WILL end up with health issues. Yes they do like the whole seeds and such. They would probably like any whole grain product.
No it's just treats for now. I'm learning on cheap stuff and they eat some of what fallsfrom the bird feeder anyway. They always have crumbles available.
Once they start laying I can get organic layer feed with no corn or soy which I plan to feed fermented a few days a week.