Sire
Um... I think your talking about wool. It has four letters and comes from sheep. :D
Horse, sheep, are two examples.
A narrow valley with 4 letters is called a "rift."
This is a breed characteristic, they are actually sheep and are called Jacob sheep.
"Rams" or "Ewes" depending on their gender.
An animal with four or more horns is called polycerate.
Isle
Dove or Crow
Pixie - which is actually 5 letters.
4 sheep 2+2=4 2 sheep: they are both in front and in back ^^
tree
gala