Minecraft wiki entry for Sheep, associated text: The first screenshot on breeding released by Notch.
A dying sheep mob.
Brown, light gray, gray, pink and black are 5 of the naturally spawning colors of a sheep.
A large flock of sheep, along with some chickens.
A baby sheep and an adult sheep.
The sheep grass-eating animation.
The baby sheep grass-eating animation.
Sheep that have been dyed by the player.
A jeb_ sheep.
A jeb_ baby sheep.
The relative probabilities of naturally spawned sheep colors.
A sheared baby sheep next to its parent. Sheared baby sheeps are available only via commands.
Snowy grass next to a patch of dirt that a sheep has eaten.
A sheep with a blue head.
A white baby sheep that has been sheared (sheared baby sheeps are only available through commands)
Z-fighting in the sheep's legs while invisible, in Spectator mode.
Rare occurrence of a pink sheep.
Sheep bugged in a tree. This is on an old version of Minecraft.
Flock of sheep in a swamp biome