You know, I consider this, personally, to be a very interesting question. Personally, I would feel that the size of the egg won't matter as long as it is fertile and all the correct measures are in place for the setting or incubating, but time will tell. I think I will subscribe to this topic to see what all our forum friends will say.
It seems related in a way to a theory I have long had. You see I sometimes think that using pullet eggs, rather than mature hen eggs, could have been one of the contributing factors in the raising of bantams. That in conjunction with selecting of runts to encourage small sizes.
I know that normally for your regular sized chicken the incubation is 21 days and I would need only 19 days for bantams. My mom use to tell me that she needed an extra 2 days for her large breeds, like buff orphingtons. So I would imagine the Jersey Giants would also need more time. I would like to know if pullet size eggs could do it in 21.
