It's mostly genetics really. I think genetics controls mainly the structure of the rack and nutrition and age affect the size and mass of rack. How old do these deer look? Big bodies? Big heads? A deer's rack won't reach max potential until he's about 6 1/2years old. Mostbucksare killed when they're 2 1/2-3 1/2 years old andnever reach their max potential. If that eight point is a young one he has potential to get bigger depending on his genetics. That four pointcould be a six point next year or even bigger, or he might be a four point again. Try to guess the age of these deer and you'll know more about their potential for the future.