I think I know what you read, that if you breed a NH hen to a Delaware rooster, the chicks will look like the Delaware dad? Hope I didnt get that backwards, LOL.
Still, really, why would you do that when you already have Delaware hens and a Delaware rooster? I dont see anything to be gained from crossing the NH in, since the work has been done and the breed created. You could always do an experiment, but I'd certainly get the Delaware rooster.
This breed is highly endangered. Most hatcheries have done what I consider a stupid thing and bred in Columbian Rocks to their Delaware lines. I think it would behoove us to do everything we can to keep the lines pure. That said, you can certainly experiment with them.