I have a dirty mind and, therefore, interpreted the sentence quite differently. To my surprise, Urban Dictionary had the same general definition:
sheep worrier (Urban Dictionary)
A male person, often of New Zealand birth, who, due to his propensity for copulating with sheep, causes said sheep to be concerned upon sight of said sheep violater. (sic)
Here comes that kiwi sheep worrier guy; look at those sheep run.
(In the USA I have heard "In Wyoming where the men are men and the sheep are worried" and "In Wyoming where the men are lonely and the sheep are worried."