Breeding to standard with a mixed flock?

[Bwillis]

I plan to free range Leghorns and mixed Bantams together, but I want to keep the Leghorns purebred. I hope to do this by culling out cross breeds. Can a Leghorn look like a Leghorn, but actually be half Bantam?

 

[CuckooOrpington]

Hi

Leghorns crossed with any other breed are highly likely to have some differences.
Crossing leghorns with your bantams will result in a genetically and visually different bird. For example, if you were to cross a leghorn with a pekin, the offspring would carry the dominate traits from the pekin. The chicks may have different coloured legs, patterning on the feathers, shape, size and laying ability depending on the parents and the dominant genes. If you want these breeds to free range together, you can cull the crossbreed chicks or, if possible, identify leghorn eggs from bantams and only incubate the leghorns.

 

[Whittni]

How about only keeping Leghorn roosters and then what ever banty hens and leghorns you want. Since the leghorn hens will lay large white eggs (not small ones!), and can only be fertilized by the only roosters there, the male leghorns, you can sell them as pure leghorns. The only mixes will be the eggs laid by your little ladies. However, if you have any male bantams in with your flock, you won't be able to sell guaranteed pure leghorns.