Johns response is pretty much spot on! So if they shipped you this snake before adjusting it there on site then it's dependent on the breeder to make sure it ate before shipping it out. Knowing my fellow humans' nature I'd assume that it was probably fed a minimal number of times before shipping so probably once... I would really focus on making him relaxed. Do your research and apply it. Besides offering food every 2-7 days I wouldn't disturb him at all. That's just what I'd do, not necessarily the best way to do things. As far as mites, I've only had it happen once but I looked in the fold of skin under the jaw and I heard from reading online that it's the best place to look at first for a quick and easy inspection.