I have a 5 month old yellow lab puppy in an apartment with me. I'm a responsible adult, so I work 8 hours a day with an hour break between every 4 hours, which is when I go home to check up on her. Now, before I get any hate comments, I feed her food with meat as the highest ingredient, take her on a walk in the morning, as well as a jog or walk at night, give her special toy to her only when I leave, and spray the walls with a bitter dog spray. I've considered muzzling her, but I'm apprehensive about leaving her alone for 4 hours at a time. I've also considered putting something on the walls to prevent her from even being able to bite them. Suggestions? And thanks for your time.