Bantams can be mixed with standards, I've done it. No harm done.My mistake. I didn't realize that standard size silkies were so rare, and that bantams are the usual.
If they are bantams, is it still okay to mix them in with a standard flock?
4+ lbs is usually the range for standard/Largefowl chickens.
LF Silkie roosters 4lbs, & LF Silkie hens 3lbs.
I own Largefowl silkies, & they can exceed that weight.
3lbs, & under is typical for bantam chickens.