The Houyhnhnms show little or no grief when one of their own die. Is this a good or bad way to react to death? Explain your answer.

This is difficult to say. The Houyhnhnms are an evolved species, more evolved than humans. They see dying as a natural progression of life which needs no idealized demonstrations of emotions. Humans need mourning and closure. We don't have the enlightened sense of life and death that the Houyhnhnms possess. So, I think shutting of or rejecting our emotions is not a good thing for us.