Our dog Heisy is just over a year old and we've trained him to LOVE his crate. I always make it a game for him to go in his crate putting a couple of his favourite stuffed toys and lots of treats easy to digest. When he was younger, we'd leave him in the bathroom (as he didn't have a pen -- but so he can walk around, but with his crate and a mat still available if he wants to nap). I used to leave my iPad with music on for him so he doesn't get startled with sounds from outside. Is your yorkie potty-trained outside or on a pee pad?
I also start telling him 10-15 minutes before I leave for work that I am going to work and that he'll be by himself so he has to be a good boy while we're away. I let him do his business one last time and grab a toy and walk him in. Now, I just say "Mommy's going to work!" and he'd run to his crate and wait for me to hand him a bunch of treats. Maybe you could leave a towel or a blanket with your puppy while you're away for comfort?
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