We are running a small trading company in our current campaign and recently purchased the rights to a 5 acre plot of land we put a small barn, small house, and really small garden on. Than we filled the rest as pastureage for all our excess horses. How many horses could we reasonably expect to keep on that land? We hired a smith to maintain their horseshoes and stuff so our dm said that combined with the grazing means no upkeep costs on the horses we keep there. The only problem is none of us have any idea how many horses would reasonably be able to live on that much land. Thanks.
The google answer is that you're looking at 1-2 acres per horse: http://www.horsetalk.co.nz/2013/01/09/graze-anatomy-handling-horses-on-small-acreage/#axzz4KA4ureW2
If you want to have an ACKs-only answer, you'll need a recent Patreon article: "Of Coins And Commerce". It mentions that a peasant family produces 16.25gp of farm goods and consumes 4.25gp of it per month. Of course these are averages and it may be that horses are on the higher end of the average, but this a starting point. Peasant family capacities are only listed down to 1.5 miles (in the updated domain rules) so you'll want to determine the number of families (possibly a fraction) that fits on 5 acres, and assuming you volunteer all of your time to keeping up the acreage (as opposed to paying someone or getting somebody else to do it), you can calculate how much "horse" you produce. how that figures into maintance is a bit tougher, you could either go by the 1gp per day it takes to commission animals or the 5sp per day to stable a horse, but both are assuming a profit for somebody providing this service.
Personally, I'd just take the google answer and call it a day. What's a better simulation of reality than reality?
The current ACKS answer is 1.33 acres per horse. On 5 acres I would allow 4 horses.
I have not yet, but will eventually, publish an article on the economics of horse- and camel-raising in AXIOMS.