New Hampshire is a Black-Tailed Red:
eWh/eWh s+/s+ Ar+/Ar+ Di/Di Mh/Mh Ml/Ml
That I can see,there is no Ml in Buff Orpington .
Your NH should have a slight reddish cast to the chicks. I think they will be darker than the BO.
Best,
Karen in western PA, USA