Pit bulls and pit type dogs can be anywhere from 30 to over 100 pounds, and skinny or bulky, so it's hard to tell.

here's a site with pictures of different kinds of pitbulls (scroll down about half way to "TEST TIME!") http://www.workingpitbull.com/amstaffpit.htm

But if you said that Kody has bad hips, they probably could use a diet.