Kouya no Tenshidomo

Miriam is an energetic girl who lives on a farm with a woman named Grace. Miriam enlists a trio of young men named Douglas, Joel and Card to help out on Grace's farm. However, they have no interest in helping Miriam and ignore her. Despite their best efforts however, they find themselves helping out after all and together end up fighting against Mister Harnbag and the corrupt Sheriff.

(Source: TV Tropes)