Eighty-three and one-third % hatching rate-very good for shipped eggs-especially this time of year! Don't worry about the issues with the markings on the chicks face or white on their down. It is a common thing for black, blue, and self blue chicks to have white/yellow on their bodies. Most will have white feathers in their first set-especially wing primaries and secondary. The majority will molt out. Very few will grow white feathers in their 2nd & 3rd set. The birds need to be about 6 months of age to be culled for the issue of white feathers. The tip of dark feathers can be injured while it is in it's infant stage, causing it to leak out it's color, which will cause white. If the white in wing feathers is inherited it will be symmetrical-on the two wings.
The feet/leg issue will need to be monitored very closely at about 5 months of age. If the foot bottoms turn out to be yellow, the shanks turn out green/willow, the skin turns out to be yellow-they need to be culled. A blue, black and brown-red can have either slate or black shanks. This was for blacks only at the beginning and later changed to add blue and brown-red. This was passed at a national meeting-either Frankenmuth, MI. 2006 or Portage, WI. in 2004. I was the one who presented the legislation to add blues to be able to have either black shanks or slate-just like the blacks at that time. The brown-red were amended also.
The dark comb at one week isn't an issue. Check the face at 5 to 6 months of age. If the face is black-called gypsy face-cull it. We raised blacks for several years before ever experiencing a gypsy face. We had to cull a few gypsy face for several years, then it disappeared.
I think the only things that should be culled at one day to one week of age are stubs, cross beak, off color-like a red spot on a black or blue, deformities like leg problems or crooked/curled toes, clean face-no muffs.
Give your chicks a chance (5-6 months) develop and breed from the best. The main thing is ENJOY RAISING the CHICKS.