Hi PP,
I guess the recipe in that old post of Rubellite's would tax most of us
, but the idea is good. We have to make some guesses here as we don't know (nor wish to) your lifestyle, income etc although it does affect the final solution. Most posts regarding food here in the UK say something like 'layers with limited treats'. No use to you. I'd suggest the following points might be useful:
Chickens are omnivores, but the original wild form would get most of its food from grass, the protein being the insects which lived on the grass (a bit like swans today which live on aquatic vegetation but consume lots of 'meat' which is living on the weeds).
Corn/wheat/grains are often considered traditional food for domesticated hens, but would have been seasonal until comparatively recently so are not essential.
Humans are omnivores so one could expect that most human foods would be OK for hens if the rules for humans are followed - not too much salt, fat, hot spices and no white bread or chocolate
. If you keep a leftover food bucket and ensure that the foods like meats, rice or potatoes are cooked and that they have lots of vegetables, then they'll end up with a balanced diet. Give corn when available and lots of water. Be prepared for them to be choosy (they are ladies after all!). There are commercial food/water additives but these seem to be a mixture of a few water soluble vitamins and minerals. Cod liver oil is good if you can get it and limeflour can be added, but, again, the mixed leftovers and vegetables should be sufficient if they are in the sun and they have access to grit.
Sorry this is not a definitive answer, but hopefully it will point you in the right direction.
Best wishes