I did an unintentional experiment with the chickens this week by running out of the organic feed I usually buy. I picked up a bag of feed at Tractor Supply, the kind they would consider to be their premium brand, but the ladies would not eat it. Egg production went way down, and we even had an egg without a solid shell. They made it through on fruit and veggie scraps, purslane that I pulled from teh garden, and whatever they could forage. They were very happy to get their regular food back yesterday.
One of the Wyandottes is broody and quite mean, so that has added to their angst. She hasn't wanted the other hens in "her" henhouse.