The planters who settled Alabama in the early 1800s already had black slaves, plus they probably didn't trust Highlanders to work in the heat. Imagine taking someone who's never seen a day over 70 degrees F and trying to work them to the bone in a Southern summer.
Plus, most slaves in places like Alabama came from plantations further in Virginia, North Carolina, etc., not all the way from Africa. Trying to get Highland peasants to come over would already be less efficient.
The planters who settled Alabama in the early 1800s already had black slaves, plus they probably didn't trust Highlanders to work in the heat. Imagine taking someone who's never seen a day over 70 degrees F and trying to work them to the bone in a Southern summer.
Plus, most slaves in places like Alabama came from plantations further in Virginia, North Carolina, etc., not all the way from Africa. Trying to get Highland peasants to come over would already be less efficient.