you can feed him hamburger if cooked, but don't substitute that for his reg. feed, also give him other forms of protein, along with his reg, feed, he's probably anemic from the mite infestation and it's going to take some time to build him back up. But don't use DE it's worthless in treating mites. Hope you also cleaned out your coop and dusted it out real good because if your birds had mites their in the coop and bedding. you right in giving him scrambled egg but corn isn't going to do much to help him get over this, it's basically just like candy is too us. and mash potatoes doesn't sound too healthy either. he needs good sourse of protein to get his blood back to normal..