I am feeding the Pruina flock raiser. I give them grass and dirt after the first couple of days. All seem to be running properly. I suspect that the lack of vitamins in the food is helped by fresh grass. I also give an egg mashed up, or tuna, as treats. I have considered getting the yeast, but never used it when I had ducks before. I never fed them anything special back then, never heard of it. Just let them out on the lawn ASAP! Here, I am bringing the lawn to them.
Purina flock raiser does have more niacin than chick only feed so I think that helps.
My tiny chicks are a week old today.
On my to do list is setting up a small outdoor space for them to have some ground time during the heat of the day. Yes they will have sun/shade option as well as dirt/grass option. One BSL is noticeably smaller. I am calling her Tina. I think they could benefit from some ground time and real sunshine.

have a lovely day
How can you call such a tiny little thing a cannon? But check out the fresh water,it only takes 5 minutes to turn it murky.
Today is nice, but we are getting more heat starting tomorrow, according to the weather forecast. The rain we had gave our well some water, YEAH! That makes for a good day, free water for lawn, garden, & chicks! A little sprinkler with cool well water is the best on a hot day.