Barney's Mom

Hi! I am new here and I hope to learn from your guidence. I have an 8mth old puppy (Beagle/Minpin mix) and he is so hyper. I had a lab/pit mix for nine years that was the best dog ever. He passed away a year ago so I decided finally to get another dog. I rescued "Barney" from a shelter. We have been through skin infections and puppy mange but my biggest problem is that he is so hyper. Constantly running around, jumping, barking, and being really destructive. Just when I think I have safely put anything and everything up out of his reach he will find a way to get to it (did I mention he was smart?). I walk him and he gets plenty of exercise but he is like a child with ADHD! I buy toys for him and things for him to chew on but he will go right past those and chew on the wall! Barney's favorite thing to chew on is electrical cords! He has chewed through my iron, vacuum, light fixtures, cell phone charger, etc. I have to make sure things are unplugged so he doesn't electrocute himself. I had stopped crating him because of the mange. I felt sorry for him being in his crate and having to scratch so much. HELP! Barney is wearing me out. I am open to suggestions. Thanks!