WATCH: Goat and rooster form unbreakable friendship

INDIAN LAND, SC - An 18-year-old goat named "Billy" and a little rooster named "Samoa" have formed an unlikely and unexplainable, though unbreakable, bond and only the two of them know why, but they aren't talking.

The two met after Billy was attacked by dogs a couple years ago and he was undergoing rehabilitation. During that time, Samoa seemed to take a liking to him, and wouldn't even let people near Billy when he was first rehabbing, says farm owner Jillian Butela.

Ever since, Samoa hasn't left Billy's side.

They sleep in the same stall, they eat together, and sometimes Samoa hops up onto Billy's back to ride around the therapeutic riding facility and farm in Indian Land, South Carolina.

"We thought it was just because the little rooster had no where else to go and the other ones were beating him up or whatever... but he's just stayed with him night and day," Butela said.