Plus, with a concentration of alpacas is also a concentration of manure and always being near the poo pile, this close proximity increases the chances of them picking up a bug or worm of some sort, further decreasing health conditions.
We have found that dung piles (when rare or no cleaning is done) accumulate until there are 2 to 3 primary piles and 6 to 8 secondary piles. These end up covering 25-35% of the acre thus reducing the available grazing space and availability of grass to grow.
I recommend body scoring at least every 1 to 2 months if the animals remain in this environment for an extended period of time. If this herd is getting diverse (i.e. 1/3 are a 2 or less, 1/3 are a 3 and 1/3 are a 4 or 5) then something needs to be addresses - more feed bunks, spacing, housing.
Barn and shelters are a bit different story.
Contact us for further discussions on how many alpacas per acre is ideal for you.