When looking through the 942 "Pasture" images at Acclaim Images.com this A Sheep in a Lush Green Field with Barn in the Background was a favorite.
All of their pictures are hand picked, availiable in a number of formats, and you can even get custom prints and posters.

Description:
A Sheep in a Lush Green Field with Barn in the Background
Stock photo of a sheep in a lush green field with just a little bit of a red barn in the background. Captured at a public park.

Some related terms for more images:
pasture,  animal,  country,  farm animal,  barnyard animals,  ewes,  farms,  grass,  sheeps,  agricultural,  livestock,  farm animals,  pastoral,  studio 33 photography,  agriculture,