I just found out that bantams and smaller breeds normally hatch earlier than 21 days. Sometimes as early as 18 days. Keep an eye on them they may pip around day 18 or there abouts. It came from an experienced incubating/hatchet of bantam an small breed birds.
X2. Bantams generally hatch earlier. However incubation temps. will effect the hatch time frame. An incubator monitored properly should keep them at around 99.5 - 100F. If your chest has them a bit lower they make take a few days longer to develop - which is better then a bit high which will cause quicker development but a higher risk of problems. If you haven't made sure the larger air cell end is kept higher up, please do so now and be aware that if they smaller end has been up they could have positioning problems rendering them unable to hatch unassisted. Hatching takes a long time. First a chick pips into the air cell on the long end (if positioned properly) and breathes that air normally for 12-24 hours before pipping the shell. The chick then finishes absorbing the blood and yolk sack into its abdomen. This step can take anywhere from a few hours to 30+ hours.
