Great to see that someone else has done it too. I started doing it, knowing how good it is for horses, then found this site:
https://www.dsm.com/markets/anh/en_US/Compendium/poultry/riboflavin.html that talks about where free ranging chickens would get riboflavin. So, I may have been on the right track for entirely different reasons. 4 eggs from henrietta.. One developed a blood ring so that was out.. 2 more were DOA and the last to hatch has curled toes and is getting sub-lingual B-1 complex. I hope it works.. hate euthanizing anything.. But if mommas are deficient, chicks will show signs. And since they were fresh eggs (after winter began) I just assumed mom was deficient and went hunting. BTW, went out to check feed and water, and poof, nearly all the alfalfa was gone in 7 pens.