There is a walled town, situated at a river ford, which maintains a militia of ~350 for a regional population of ~1000 farmers, rivermen, minor estates, townsfolk etc.
I feel that I'm getting the hang of some of the logistics, but when it comes to horses I'm stumped.
Basically I'm wondering how many horses it would be fairly efficient/flexible to have on hand for this militia.
VERBOSITY ALERT: for the rough-estimate-breakdown, please just skip over all the excuse-making to the last bullet, "So at a guess, . . ."
this is allodial land; no local resource or other duty is owed outside the region.
the 350 out of 1000 is based on a rough estimate of population distribution in which the total of able-bodied females and males, eligible from ages 15 through 35, hovers around 400 ... minus ~44 pregnancies and parents exempted while caring for children under 5 (~90 of those), minus another ~6 citizens wealthy + preoccupied enough to pay to not-'play'. (these last are each taxed the equivalent of the council's expenses for a member.) Only about 300 of the 1000 live within the town walls.
on average, in peacetime, about a tenth of the militia is on duty each day; each member owes 3 days of guarding (street patrols and/or wall watch) and at least 1 of training per month. Presumably, horses are not particularly useful to whomever is on wall duty. I started thinking about 15 on the wall, 15 in the streets, and the least experienced doing go-fer/messenger stuff, but then thinking about trade escorts, scouts, and outlying territory, that's when I got stuck on the horse thing.
irregular duties include light escort of trade caravans passing through the region. Activity of bandits, monsters or other hostiles isn't frequent but isn't predictable either, so most caravans will already have hired some of their own muscle.
forest has been cleared for several hundred miles in every direction, but the land under militia protection can be assumed self-sustaining in matters of wood as well as food/feed. ~20 small estates spread out past the opposite banks of the river and further 'down-road'. The largest city on the continent, pop. over 100,000, is ~3 days' ride from town, directly away from the rest of the lands under militia protection. OTOH it would take ~5 days to ride the other way down the highway and out of militia 'jurisdiction'.
magic is close to standard AD&D - main subtypes arcane/divine, etc. but arcane is a rarefied pursuit and if the odd militia member is 'wizardy' their primary functions would be artillery and/or fortification.
local religion isn't preoccupied with horses beyond their agricultural utility; low-level cleric-types may be peripherally involved in the stables, but the council doesn't ensure divinely-fueled equine care. If a member is slain in the line of duty (s)he will be brought back from death by a high priest (only one locally available) at council expense if possible, but a member who loses a horse is responsible for replacing it.
historically there has not yet been a reason to field the entire militia simultaneously, outside the walls + mounted. Invasions and raids do happen, though not like clockwork, and each hamlet and estate in the region has a small fortified townhouse and its own stable(s), but the general idea with any large-scale threat is for all 1000 citizens to take refuge within the town walls. (Might have to enlarge the town itself to account for emergency stabling ...)
So at a guess, on any given day (at least in an 'averaged out' sense) there are ~20 horses in militia use in/around town, plus a few more at each outlying manor, a few running messages or other militia business between 'stations', maybe a few escorting a caravan, a few being used to train new recruits ... So if this means close to 100 horses in day-to-day circulation, how many more might be on hand to accommodate occasions like emergency evacuations, or keeping a 'fresh' reserve for rapid communication or surveillance?