It sounds like it is lacking convadanice bit shiy it will be better with terriers that are working it will see what to do just dont get angery with it an shove it in a bush then it will think it has done worng and just heal alongside.
I WAS GETTING THAT PROBLEM TILL I GOT A BETER GUN AND SHOOTING THEM JUST UNDER THE EAR ON SIDE HEAD SHOT FROM 25 TO 15 YARDS AND USEING HOLLOW TIP PELETS
you need a good windy day a bit dull maby rain walk in to the wind wher u wont to coruse hairs like to lay flat to ground approch quietley with dog on slip it shuold jump up and run when u get close slip dog and stand still