Alittle off the topic of white leghorns from a hatchery but follows the conversation
Me being the bored chicken breeder that I am, I have lots of time to plan out breeding set ups of imaginary breeds/crosses. One that I keep coming back to is the basic white araucana cock on white leghorn hens. Hatch tons and keep the first dozen or so hens that lay blue eggs first. Pair them up with a white leghorn cock and repeat the same thing, just keep the earliest laying blue egg layers. When we had true araucanas our hens laid earlier than the other colors and some of the tailed smooth faced chicks we got had a body that looked alot like leghorns, I think based on the clean blue eggs and some white in the earlobes that maybe they were crossed in before.
Our main sexlink pen this coming year will be easter egger based. We have the basic silver laced wyandotte and barred rock hens that were going to be crossed to a rhode island red rooster but he wasnt the best bird, very agressive, had a crooked toe and crooked keel so he went away. We were at fair and a lady had a pair of easter eggers from her flock, they were 1/4 RIR and 3/4 BBR colored easter egger. They looked just like hatchery RIR's in color and shape but with beard/muff, green legs, and pea comb and the hens lay a fair amount of green eggs. The rooster didnt like the lady, she said if someone didnt take him he would become stew but he was too pretty. We took him home, the name Stew stuck, he is red based so will work for sexlinks. He will be the main sire of the largefowl birds. He will be 'visiting' the brown leghorns and easter eggers too just for layer chicks.
So we will get the hybrid vigor from the cross, hopefully green eggs, and the sexlink ability. I would love to find some hatchery white leghorns to use for layer crosses. This coming spring I have a whole list of projects involving hatchery birds and white leghorns are on the list.