Don't confuse auto-sexing with sex-linked. Auto sexing birds will carry this trait from one generation to an other as long as you don't mix in blood from a different breed. Some of your auto sexing birds are PBR, Cuckoo Marans, Dominique. You'll notice that the common trait is the barring, or similar to barred feathering. Other auto sexing birds are any of the "something"-bar, ie: leg-bar. There are a few other breeds that a well trained eye can distinguish at hatch. But, these would not be autosexing across the entire breed, more specific to a particular line within that breed.
As previously stated, sex linked birds are from a specific breeding of one breed of roo to an other breed of hen, and will either be black sex linked, or red sex linked. Any future breeding of a sex linked bird will not be sex linked, but will still be a nice bird!. Then there are the crosses that can be feather sexed. That's a topic for an other day, and a topic that I wish I understood.
