Breeding commercial leghorns question

We ordered three leghorn pullets with our Isa Browns this spring. Two of the leghorns have developed combs and wattles very early and I've been thinking I had two roos and only 1 pullet. Well, one of them crowed a few minutes ago - confirming my suspicions. My sister has always wanted a leghorn roo (she lives with me) and of course she is delighted so guess I'll be adding another rooster to my stock this winter  

My question: Has anyone had any experience breeding commercial leghorns? Will they breed true or not? Not that it really matters to me. I will just run him with my commercial layers which I hadn't planned to keep a roo with so if we hatch any of his chicks they will just be replacement layers for us. We won't be selling them. Just wondering as I've heard that comets/Isa browns won't breed true so thinking maybe its the same with the commercial leghorns.

Well, they'll breed true in the sense that the offspring will all be white leghorns, and will lay white eggs. My understanding (someone correct me if I'm wrong) is that commercial leghorn breeders also follow the "four inbred lines" school of breeding.

The consequence of this is that the offspring of a mating among your birds will likely be considerably more variable than those you buy as day-olds. Still, I would think they should be just fine for a backyard flock; I'd have no hesitation about doing that.

The reason the ISA browns and Red Rocks don't breed true is that they're the result of a sex-linked cross between two different breeds of two different colours or patterns, and the gender of the offspring is recognisable at hatching. Mating among the hatched crosses will result in a multiplicity of colours (and sometime patterns) that is not predictable by gender.

ipf wrote:Well, they'll breed true in the sense that the offspring will all be white leghorns, and will lay white eggs. My understanding (someone correct me if I'm wrong) is that commercial leghorn breeders also follow the "four inbred lines" school of breeding.

Yup. ipf as far as I know the commercial white layers are a four way cross with a male line for the K gene and female line for the K gene so they can be sexed easily.