I hope this might help someone else.
Thursday morning, 4 of 8 poults started flipping over and thrashing, heads thrown back. Right away, I gave them some beef heart and B complex. 3 semi recovered within hours, but one did not. The 3 were better, but not their usual rowdy selves. I was pretty sure I would lose the one who wasn't better. He continued to seize off and on and was getting weak. Today, I remembered something. Alfalfa. I ran down to the barn for some alfalfa cubes and soaked them in my fermented food until they were soft and broke apart. I fed the 7 a mix of the alfalfa and FF. Within a short time, they were running around, flying and launching off the waterer and heater. The 8th (and oldest) was in a crate by himself. I tried to get some fluid from the alfalfa/FF mix down him, but not much luck. I put a little in his bowl and went out to care for the other birds. I've had a few of the younger poults in the coop acting a little off, so I took them the same mix. When I got back, I noticed the poult had eaten all his food and looked brighter. I gave him more and he ate most of it. He was crying for his buddies, so I put him back with them. I can't tell there was ever anything wrong now. This is a vitamin A deficiency. I normally start feeding a little alfalfa around 3-4 weeks, but I totally forgot this time. Lesson learned!