The Further Adventures of Hank the Cowdog (Hank the Cowdog #2) by John R. Erickson

The second book in the Hank the Cowdog series opens with Hank defending the ranch against the attack of a Silver Monster Bird. Later he is stricken with the dreaded disease, Eye-Crosserosis, and unless he can find a cure for this dangerous condition, his position as Head of Ranch Security is at stake!

In his quest for the cure, Hank visits the cave of a witchy little owl named Madame Moonshine, and some crazy adventures follow.