@guk Oh god, I'm sorry to hear. That sounds really rough and with all the negative build-up I get that it's really hard to train him to want to stay in there.
Susan Garrett's crate games supposedly are the go-to when it comes to crate training and come highly recommended. I haven't used them myself, but if you want a solid program, I figure that would be it. She's got an excellent podcast as well, and her insights have been extremely valuable to me.
You could also try a combination of Kikopup's Capturing Calmness and Karen Overall's Relaxation Protocol, modified to fit the crate, of course. If you get the crate closer to where you're working, it'd be relatively easy to drop in a treat at regular intervals and praising calmness. Far as I've read, working dogs have a hard time learning to switch off and learning to relax, so it's something that needs to be trained. Both those options come highly recommended for dogs who don't know how to chill the heck down and they're all about training calmness. Plenty of people in this sub and the dogtraining one will swear by them and they've seen excellent results.
As a third option, you could try long lasting chews. Cow's ears, ostrich bones, etc are all good options. Ostrich bones are particularly good for dogs with food sensitivities, they're absolutely massive and supposedly excellent for cleaning teeth. Chewing also tends to be a relaxing activity for dogs and releases all the happy hormones. I wasn't particularly keen on it when I got them at first because it felt like cheating - ours is fine in the crate but not so much so in his pen, so it's a work in progress - and they made him EXTREMELY wired and excited at first. Slowly, as they became less of a novelty item and more of a regular fixture, they're now a welcome pacifier at the tail end of the day and he's learned to chill out and nom them for a good stretch. If your pup is a relatively easy going or even medium chewer, it'll take him a decent while while to get through it.
