I've also found that a broody will direct her chicks to eat the adults’ feed, but the chicks largely ignore it in my experience (perhaps intuiting that the whole grains are too big for their system to comfortably manage). I base my chick feed on recipes in old poultry manuals, which you may or may not find useful or interesting; the broodies here all like it so I don't need to offer them their usual feed as well.Léa doesn't want to eat the chick's starter. I gave her grains and she enthusiastically gave some to the chicks...whoops...
For the first week, chicks here are offered chopped boiled egg, milk- or fermented-feed-liquor- soaked breadcrumbs, and oatmeal, mixed into a crumble. Thereafter I add, increasing in quantity and variety as the weeks progress, fresh curd or plain natural yogurt, live mealworms (small ones), mashed tinned sardines, peanut butter, currants, polenta or semolina, smashed Weetabix or Shredded wheat (local whole wheat breakfast cereals), and smashed dry high protein dog or cat food. They forage with the broody all day too of course and eat whatever she identifies as food.
Chicks eat little and often, befitting the tiny size of all constituent parts of their anatomy. Supplied food is presented in small particle size or of soft consistency. It is easiest to eat in a crumbly consistency, not a powder, and not so wet that it sticks to the beak. When they are out on the ground, their broody will find and direct them to eat grit, hopefully of an appropriate size, but they use their own judgement too.
Inclusion of some live yogurt soon after hatch will inoculate the chicks’ gut with lactobacilli (at least), which will help them deal with the coccidia that they are bound to encounter outside. The broody may direct them to consume some dried chicken poop for the same reason (faecal transplant to get good bacteria into the chicks’ gastrointestinal tracts). Yum

