On leash outside or fully fenced.  Many Tubes! 5 Levels

Rat Trap 1, 12 to 20 tubes, 1 rat, no dirty tubes
Rat Trap 2, 12 to 25 tubes, 2 rats, no dirty tubes
Rat Trap 3, 12 to 25 tubes, 3 rats 1 dirty tube
Rat Trap 4, 15 to 30 tubes, 4 rats, 2 dirty tubes
Rat Trap 5, 15 to 30 tubes , 1 to 4 rats, 2 dirty tubes.

Scoring: 10 faults calling wrong tube
Level 1,2,3, two faults allowed
Level 4,5. 1 fault allowed
Rats not to be rolled around a lot. Handler can pick up the tube.
Secured on flat area, not to roll.