This is my theorization on hippogriff genetics One parent is of course the griffin,which will pass down the eagle parts to the offspring. However,the other parent may either be an earth pony,or a pegasus,or a unicorn,or even an alicorn. The earth pony will pass down the horse parts The pegasis will pass down the horse parts,and wings The unicorn will pass down the horse parts,and possibly the horn and inate magical talent The alicorn will pass down the horse parts,the wings,and possibly the horn and inate magical talent