Good point. My purpose of this experiment was to compare the way I raised chicks a few years ago with the way I raised them last year and the way I hope to raise them in the future.
Another discovery which I plan to keep a closer eye on is pasted vent.
Group 1 had several with some degree of pasting, 2 were severe.
Group 2 had just slightly less and only 1 severe.
Group 3 had very few but 1 was severe.
So after 1 week, my takeaway so far is that the FF somewhat limited pasting.
I think having chick grit available helps with pasting. Do you have chick grit available?
Without going back and quoting your methods ... I think what you are doing is super cool. I'd like to know more about the yeast and probiotics you're including. What brands? What concentrations? I'm also adding a couple of supplements to my FF, but I add them just prior to serving, not during the fermenting process.