I have completed the low stress stock handling course with this group: https://www.lss.net.au/trainers.htm
They were very good, putting into words what experienced handlers probably didn't even realise they knew. We also applied the principals to multiple livestock species, including horses. They also challenge some common mistakes/theories that people develop over time that may be causing them grief without them realising. They say it's more of an 'advanced stock handling' course, but they offer training for all levels of expertise. Our organisation brings them in every year for training, so I'm not sure where you can go. I dealt with Chook and he was great.
Hope that helps.