So I looked for information on the net, and I found out that as long as your pet yukkuri (even a breeding yukkuri) is registered, there is a place nearby that holds a run they can enter. Incidentally, I took care of the pet registration at the nearby shop where I bought these guys. Since it wasn't something formal like a pedigree or anything, an anticlimactic amount of paperwork was quickly finished, the printer made a "PIIGAA" noise, and the result was me carrying the printed registration card. Along the way I caught these guys nervously pitter-pattering around the whole time, keeping my own little bit of excitement absolutely secret.On Sunday morning, we did the "Yukkuri Run." They were noisy yesterday, but at the same time I realized that these guys were much more energetic than I had thought. They say that yukkuri who are originally meant for breeding are supposed to be raised in fish tanks or small boxes, but actually wanted, with all their hearts, to run in the spacious fields.