I often run field trial setups as singles for young dogs in training.
There comes a time when the young dog is ready for easy multiples but I still run the bigger setups as singles.
Here is one way to transition the young dog to running the bigger setups as multiples. In this video, we have thrown the long bird first then the shorter mark, this would be the 3typical order for the throws in the derby.
After the pup returns with the last mark thrown, I have him set up on the memory bird. When I believe he is looking out well I have the thrower on the long mark do a silent rethrow of the mark.
This way the pup sees the double thrown, He has to pick out the long gun on his own, and then the rethrow is a big reward for picking out the fall, and he gets to run the long bird as a single.