The feeder should be big enough they don't run out of pellets between feedings. There should be no doubt they will have food 24/7. You should also be feeding unlimited hay so they should have 2 possible food sources 24/7. I'm am not certain if hay has enough sugar sources to maintain blood sugar very well and how long it might delay things.
I do not agree with keeping young chins inactive. Maybe there is something different that makes it necessary for some people.
I have found mine gain weight twice as fast having big cages, levels, and out of cage time from the day they are born. We have lost 1 since starting this and it was in the smallest of cage sizes we are still using with the fewest obstacles. Ours bound about entire rooms and have wheels as soon as they are steady enough on their feet. No seizures, no overheating symptoms, none of these supposed blood sugar problems, no injuries.... They are highly athletic quite early, well muscled, fluffy, and like I said gain weight twice as fast as those raised without as many exercise opportunities. If I was having lots of seizures due to something so simple as basic exercise and there was not an obvious fix like diet changes I would remove those and the related chins from breeding.