The weight of the parents can certainly give a good indication of the weight of your pup at full grown. There are so many different approaches to breeding boxers - some breeders focus on the north american approach which is a smaller frame topping out at about 65-70 lbs for males. Others bring in European stock and focus on a more filled out frame which tops out at 90-95 lbs for adult males.
At 6 months my pup was about 45 lbs - she is a European boxer, and I fully expect her to be 80-85 lbs at full grown. My guess is yours is on the same track, and as a male would be closer to 90. How big is the father?
btw.. I'm feeding about 2000 calories a day right now... and I expect it will be like that for quite some time to come - probably until she's at least 3, then it will go to something like 1500 calories a day. I assume your boy is eating well?
