That leg does look a little funny. If he does have MBD it's just the onset of it. Make sure you are giving him his supplements. Calcium with d3 twice a month, multivitamin twice a month not to be given at the same time, and calcium without d3 at every other feeding. Replace the UVB bulb like you said. I don't think he looks dehydrated, but the best way to know for sure is to look at his urate (the white part of his poop) if that is brown or rusty looking then he has a hydration issue. It's best to gut load your feeders with turnip greens, dandelion greens, mustard greens, butternut squash, bee pollen, and various fruits. Then by a quality dry mix like cricket crack. Flukers is basically useless in my opinion. I would bring his basking temp up about 10 more degrease that could be one reason he doesn't seam active. might give him a better variety in his diet as well. Things like super worms, silk worms, Dubai roaches, horn worms. Things like wax worms, and mill worms should only be given as a treat do to poor nutritional issues.