I have 10 chicks that are 3 weeks old. Any ideas what sex and breed? Thanks
All of the ones that you label "Roo?" look to me like they probably are males. That is #1, 4, 6, 8, and 9.
Maybe #7 as well.
Where did you get the chicks? That can often help narrow down the list of possible breeds.
My first guess would be backyard mixes, hatched from eggs from your own flock or from someone you know. In that case, likely few or no pure breeds among them. If you know the exact breeds in a flock like that, it is often possible to pick out which parents must go with some of the chicks, while other chicks remain a mystery.
If you bought them from a store in the USA that orders from any of the major hatcheries, I would guess that #8 is a Silver Laced Wyandotte (rose comb), #10 might be a Red Sexlink (also called Red Star, Golden Comet, and various other names.)
You might have a bunch of Barred Rocks or Cuckoo Marans, or maybe some of each, possibly with some Black Sexlinks mixed in. Barred Rocks should have yellow feet, Marans should have white feet and may have a few feathers on the feet. Black Sexlinks often have yellow feet but could sometimes have white feet. White vs. yellow feet can sometimes be hard to tell when they are young, but yellow feet get brighter and more obvious as the chicks get older.
#10 is the right color to be a Red Sexlink pullet (could also be called Red Star or Golden Comet or various other names.)
#9 has the right feather colors to be a Red Sexlink pullet, but that comb looks right for a male. So either that bird is something else, or it's a pullet with an extra-big comb.
I'm not sure about the white ones. Cornish Cross, White Rock, and White Leghorn are three common breeds that have white feathers and single combs. The males of Red Sexlinks are also white with single combs when they are young, although they often show some other colors when they are older. All of those would have clean legs (no feathers on the feet.) White Cochins would also have white feathers and single combs, but they would have feathered feet. The white chicks are busy sitting on their own feet so I can't tell.