Alpacas are herd animals and can best be kept with a minimum of two. If you do not want to breed, you may have castrated males or young males. A small herd does not need much pasture. However if you want to breed alpacas it is necessary to have two separate pastures : one for the males and one for the females.
If the alpacas are in an open field they need a shelter against rainfall or heat. A small indoor housing should be provided for them in the winter.
It is important to clean the pasture regularly from feces. It would be better, if there is sufficient grass land, to rotate the animals from pasture to pasture periodically.
The fence should be at least 4 ft. high. Electric fencing or barbed wire fencing should be avoided.