Scout is a 20 month old neutered lab who on the whole is very good. She is keen to please and is obedient. However, in the last few weeks she has become really difficult to get back at the end of a walk. She just gets a naughty look in her eye and I can’t get close to her without her running off. She does the same for my husband and we can be out for hours trying to catch her. Food doesn’t work at all as when she’s in this mood, all she wants to do is play by dodging us when we try to approach her. We have a large green outside our house where we regularly play fetch with her. She used to do this beautifully but now, after a few throws or even straight away she will just start running off, trying to get us to play chase with her. This is becoming a real problem as its becoming difficult to take her out and let her off the lead. She will come back beautifully when called, for a treat, or without a treat most of the time. It’s just out on the green outside our house, or at the end of a walk where she really plays up. Does anyone have any suggestions as to how we might break this cycle?