so yeah do they? My bantam eggs ware more developed than the others they already have the full spider thing when the regulars are just starting to show fertility?!
Some people say that they do, and in general, smaller animals (dwarf rabbits vs Flemish Giants, Pygmy goats vs Kikos) do tend to have slightly shorter gestation periods than larger animals. The same may hold true for chickens. However, my bantam eggs have always taken the same period as my regular chicken eggs, even when incubated in the exact same conditions, under the same hen. I have Cochin bantams and Old English Game Bantams.