You also could have had incubator problems. If they started hatching on day 21 your temp was probably good but your humidity during the first 18 months could have been to high which makes for a small air space in the egg and chicks drown. Or your humidity during hatch may have been too low and and they dry out in the shell. Hygrometers and thermostats can be way off.I first look at feet-- that is a must. Check that they have all 5 toes on each leg. No extra nails, etc. If that is okay they move on. If not-- they are gone. From there, I'm checking wings-- most of mine have nice big crests anyway. But I do think the crest is important. If it was on the smaller side for a crest, I'm not so sure I'd keep it. Look for split wing when they get older. That is a DQ, and don't breed with that. I agree with Peep-- type is also very important. My birds that don't look "quite right"... I just sell them off. My goal is not to have tons of birds, but the best birds. Even if that means I sell off over half of what I breed. I've already been selling chicks with obvious faults. But the rest, I'm ify on and I'm going to keep them at least until October to see how they turn out and then sell them off, too.
That is a shame! I've bought a batch of eggs and NOTHING hatched! Sometimes that is just what happens. I just jumped right back in and bought more eggs. You have some good hatches and bad off of shipped eggs. They are going thru a lot of bouncing around at the PO. If you were having fertility issues though-- no growth, find another breeder to buy eggs from.
