The sheriff couldn’t do it in two tries what this farmer did

A farmer lived on a quiet rural highway.  The traffic was so heavy and fast that his chickens were being run over at a rate of three to six a day. So he called the sheriff’s office and asked for some help. The sheriff put a sign, but it didn’t work. Three days later the farmer again called and said that the sign seems to make the drivers go faster. So the sheriff again put a sign. But still it didn’t work. The cop couldn’t do it in two tries. So the farmer decided to put his own sign. After that he didn’t call the authority. He did something amazing what the sheriff couldn’t do it in two tries.  Read to know what sign he put.