I've been fermenting feed for 8 days now, feeding it for 6. I started with 1/3 cup whole wheat and cracked corn combined with 1 cup water and half a tablespoon of Bragg's vinegar (I'm feeding just 3 pullets as a supplement to their regular feed). After two days I still hadn't seen any bubbles, but it smelled like bread instead of like vinegar, so I drained and gave some to the chooks. They gobbled it up! I've been feeding it to them daily, adding more wheat and corn, then a little oats, water as needed, and once another little splash of vinegar. After 5 days of fermenting, I finally saw bubbles and the mother! I never remove all the feed, just take out as much as half, and add back as much as I remove, and give it a good stir. I can't believe how they wolf it down.
I don't know if it is related, but for the last couple of days they've started following me around when I let them out of the coop, instead of running from me. I am now their favorite person.