An example of bad behavior and it is completely my fault.
Working two dogs at the same time can be done but it's not easy. In the above vid Emmie was not supposed to be walking at heel so she's not really disobeying. The simple fact is that I should have placed her at heel and then given the retrieve for Carson. Then if she ran-in to try and "steal" the bumper I could have rightfully corrected her, and she would probably expect it.
The difficulty here is that the retrieve is so important to her that it might be worth it to her to be corrected if she were able to get the retrieve. It's something I am working on, and actually in the previous vid of Carson doing the unseen retrieve Emmie is actually behind me at "hup".
At first blush it seems that if I had all day to do it, and the training grounds were my backyard, I could work them each independently to the level I would be happy and then bring them together. This is something we do, in terms of yard-work. I do place-board training with them independently. But eventually in the real world, day-to-day they will need to both be with me at the same time. One will work, while the other is at heel and then they should switch out.
So on training walks like this one where I'm working them together I'm going on the theory:
"it's better to set off as you mean to go on".