I feed my flock a 50/50 split of local milled pullet grower crumble and fermented wholegrain wheat/peas/oats with meat meal and seaweed meal added. Free choice oyster shell and fed back egg shell. Some table scraps. Plus they have a range of pasture species to graze on and whatever bugs they can find. They get garden waste and weeds and I fertilize with liquid fish so there should be some good trace elements there.
They're super healthy and shiny, moult quickly, their eggs taste amazing and the yolk colour is astounding, their eggs hatch strong healthy chicks, and my chicks grow well. Commercial feeds are formulated for laying hens that are supposed to lay like machines for a maximum of 18 months and then be culled. That's not the situation I'm dealing with. My flock are not production hybrids and I expect them to live 5+ years.
If I can be trusted to feed my own child a healthy balanced diet I'm pretty sure I can feed my chickens a healthy balanced diet. My child is also healthy and growing well, although I can't brag about her pre-teen attitude