Training a puppy to handle long 12-hour shifts requires careful planning and adaptation of their routine. Firstly, make sure that prior basic obedience training has taken place so that your puppy knows and understands commands like sit, stay, and come. This will help in managing them during the long work hours. Gradually increase the duration of time you spend away from your puppy, preparing them for the extended periods when you're at work. It's important to hire a dog walker or pet sitter to come by mid-shift to let your puppy out for potty breaks and exercise. Provide interactive toys or treat-dispensing puzzles to keep them mentally stimulated during those long hours without your presence. Set up a designated sleeping area where your puppy can rest comfortably during their downtime while you're away. Remember to spend quality time with your puppy before and after shifts so they still receive social interaction and bonding despite the long hours apart.