well sometimes a good correction when herding is needed, it's not pretty to see a dog just zone out and decide to really get "on" sheep.
At one point, I wanted to try out a new instructor, took my female aussie. I told her Jynx was afraid of keys, and I mean she shuts right down if you chuck keys at her, but she'd been on sheep a few times before with a seasoned handler and he felt she really had what it takes to get into herding..
Well whats the trainer do, gets out her keys,,had the dog outside the pen and chucked the keys at her 4-5 times just for going near the fence
( I was NOT happy. When we took her in the pen, she had already shut down big time, wouldn't even LOOK at the sheep. Needless to say, I was VERY unhappy with this instructor who'd been doing this for years..
I thought I'd have to deprogram since she'd turned into a marshmellow
The following weekend I went to an Instinct test, told the instructor what had happened, we let her in with the sheep, and tho she was tentative at first, she got back into it pretty fast so it didn't leave a 'lasting' impression..
So, with that, keep going and see how he recovers,,it may take a couple more tries or who knows he could be fine next time you go,,kinda stinks tho when one thing can really make them shut down