Beards are under the chin, muffs are on the sides of the face.
The same gene causes (or prevents) both of them, so a chicken who has one will always have the other as well.
If they get the wrong rooster siring chicks one year, the rate of brown eggs in his daughters could be pretty high-- and since a rooster doesn't lay eggs, they won't even know until his daughters start laying and the customers start complaining.
The crossover rate is supposed to be only about 5%, but you don't see it until a given female happens to get two copies of the not-blue-egg gene, by which point it's probably carried by quite a few members of the flock.
Pretty much anywhere that sells Easter Eggers says that they sometimes lay...
I thought it meant they had two or more flocks, but were selling all the chicks under the same description instead of listing them as two different kinds. Personally, I'd prefer to see the two kinds listed separately, but like you I do appreciate that they are trying to truthfully describe what...