As you might suspect from the title, 1958's "Once Upon a Horse" is a western farce. If the title didn't give this away the casting of the night-club comedian team Rowan and Martin might have; of course this was 10 years before "Laugh-In" made them famous. Prior to this the western genre only rarely got a feature film comedy treatment, Bob Hope had a couple successful efforts shortly after WWII ("The Lemon Drop Kid" and "Son of Paleface").
"Once Upon a Horse" is not particularly funny but it is pleasant enough viewing and the production design is better than that of most "B" westerns. The casting of Dan Rowan (the Dick Smothers portion of the comedy team) and Dick Martin (the Tommy Smothers portion) seems rather strange as the script gives them little opportunity for their trademark verbal comedy and the only really good visual routine is Martin's beer drinking sequence. Fortunately Martha Hyer and Nita Talbot were excellent at subtle comedy and manage to inject enough minor laughs to keep the film from bogging down.
The Rowan and Martin characters are cattle rustlers who find themselves in a down market for beef. They discover that their new herd is worthless and that feeding cattle is expensive. Miss Amity Babb (Hyer), the local saloon owner, controls almost all commerce in the area and ruthlessly price gouges everyone. An ongoing gag concerns how predatory business people are bigger and more successful crooks that those who are openly dishonest.
Hyer has never particularly impressed me as a straight dramatic actress, but she knows how to gently tease a comic role. It is essentially her film, she looks gorgeous here-absolutely at her physical peak (also seek out 1957's "Mister Cory"). And her wardrobe is an excellent example of costume people earning their paychecks.
Then again, what do I know? I'm only a child.