I think it people don't understand them, I've seen dogs with more brain then their owners and read a hunting situation better than the person involved, personally I like just enough brain so they know the score but not enough they start thinking or making there own decisions very fine line. Plus most are used to sighthounds or terrier bull blood that bit more tunnel vision and hunting style then they try it with a more heavier collie type and break them, and that's my opinion on the ones I've seen start get fussy or stale on game it was the owners that have caused it ( not talking about the ov