Drover is Hank's loyal yet timid sidekick. The "little white mutt" is usually found hiding in the machine shed. He has a bad leg which -- coincidentally (?) -- acts up when the action is hot like in the following excerpt:
[Hank:] "Hang on, Drover, here we go!'
[Drover:] 'Oh, my leg...'
We zoomed in for a look. Sure enough, it was Tuerto of the Gotch Eye. When he saw us streaking towards him, he tossed his head and stamped his right front foot. It was pretty clear at this point that he had no business in our home pasture.
'Hank to Drover, over. Confirm visual sighting at eleven o'clock.'
'I thought it was only ten o'clock.'
'Roger, but suspect has moved one hour to the south.'
'Time sure flies when you're scared.'
'Roger. Suspect has invaded our territorial territory. Prepare to initiate Growling Mode!'
'Hank, let's don't growl at him. He might think we're being unfriendly.'
'That's the whole point, Roger.'
'Of course you are. Ready? Mark! We have initiated Growling Mode One and are proceeding toward the target!'"
From Hank the Cowdog 8. The Case of the One-Eyed Killer Stud Horse