Latifundia, from "latus", meaning extensive, and "fundus", meaning farm or estate, are featured in many fantasy setting, like Game of Thrones, Elric of Melnibone, and Warcraft. While ACK contains rules for settling slaves on domains (ACK core, 251-252), these rules seem better suited to representing settling slaves as tenants/sharecroppers/coloni/serfs than the even more brutal and exploitative practices that chattel slavery makes possible. Thus, I created these rules for my own game, in which bands of guerrilla beastmen struggle against dastardly imperialist dwarves.
Firstly, domains exploiting chattel slaves (rather than exploiting them as the equivalent of serfs or coloni) have a separate domain morale scores and levels; one for coloni and another one for chattel slaves. The slaves' morale score is equal to the colonorum morale score minus 1, or minus 2 or 3 if the slaves equal 50% or 75% of the domain's total population respectively.
Secondly, the proprietor may raise land revenue from the slave families. Every 1gp of extra income per family lowers the morale score by one and increases the number of d10s rolled for negative population growth by 1.
On average, each extra 1gp per family will cost 1,100gp in slaves. Thus, this system encourages the creation of large latifundia with thousands of slaves. It's also quite uneconomical. Like in the ancient Mediterranean, latifundia owners must take advantage of low slave prices or have access to war booty in order to function. A society in which latifundia owners are the dominant political bloc will engage in lots of genocidal wars of rapine and conquest, like the ancient Romans, in order to keep many cheap slaves in stock.