I have been selectively hatching only my largest eggs from my biggest pairs, only have two pairs that I would consider extra large(weighing in at 13 &14 oz), their eggs are huge compare to my regular jumbos eggs. I have two that are almost 4 weeks old and they weigh in at 10 oz and 10.5 oz. They are the largest I have raised at that age yet. The other 8 are only 1 week old and then 2 hatched yesterday. I am only getting about 80% hatch rate on the eggs from these as oppossed to 98% hatch rate with the regular jumbos. My camera isn't working at the moment or I would post you some pics of these two young ones.
Matt