The culture of the area has religious institutions that take in unwanted children, Asani was raised by the priests and Talia sent all of her kids except her eldest son to be cared for by the temple. It is entirely plausible that the couple are sick fetishists and simply sent all of their sons to be raised by the temple' priests and priestesses.
Fun Facts: This alone makes Zeta(just now remembered the city's name

) more ethical than the Romans who had a religious obligation to leave unwanted babies at the local dump, girls were more often abandoned than boys because they were thought of as requiring more care, and slavers and slave owners who wanted a free slave would visit the dump to pick up what they could find, consequently some Roman fathers would mark their children before abandoning them to make sure they didn't fuck any of their own daughters at the local whore house.
Okay I got confused not realizing you had a part under the spoiler and a part that wasn't
SPOILERS AHEAD ( because I somehow always have trouble adding a spoiler tag on the phone)
Zeta clearly values increasing their population. The last time the Romans were on about that they grabbed and graped all the Sabine women.
Regarding Talia, gotta say... What that chick lacks in high level attractiveness, she sure makes up in drive; guess that's her reproductive strategy).
You could be right about them giving away all the boys, although I don't know it seems unlikely. It could be the case, though.
It's worth noting Shani specifically decided to become a stalker to make her Daddy proud, so maybe he wasn't looking to have a stalker follow him up, but just decided to let her go there because she wanted to. In that case he wouldn't have been as likely to focus a male heir, it's true.
And you're right if they were trying to just create a little bubble world outside the city of hot tail and hotter tail, it would make sense that they would hand over the boys.
I'm not so certain that Zahra would have gone there, though, as she gives me vibes of a woman who would hold on to her offspring tooth and nail. Maybe the aforementioned kink pwr lvl exceeded her motherhood pwr.
It would also mean they had multiple female children back to back and then a batch of male children back to back; usually those things are a little staggered out, although not always.
Anyways, it's definitely something that's worth considering because obviously they don't feel like a normal setup, even in a much more sexually permissive society.
Actually I just thought of one possible negation on that idea
Kataryna basically comes in as a gift from a friend with the understanding that she's not technically a slave but a concubine which means that there are certain responsibilities to her and Igor w/her, even though she's *almost* a slave.
So if SHE pops out a boy she would very likely want to hold on to it because she DEFINITELY has STRONG maternal instincts. I mean the way they wrote her although she's fascinated with MC when she finally gets there she's all "gimmeakid! gimmeakid! gimmeakid! gimmeakid!", and it's actually suddenly NOT really as much about MC. I'm guessing the reason she was fascinated about him was that she just assumed he was super virile, probably due to some of the not particularly tall tales that Igor would be telling her.
This would mean that if they knew the boys would be given up they'd have to have given her a pre-fvck-in WARNING to that effect BEFORE she accepted her concubineship and I seriously doubt Kat would be on board with that.
She is clearly all business with having babies and it doesn't seem like she would be focused on only females.
I mean with Kat it's kind of amazing that she fled her village which was DEFINITELY going to keep her flat on her back and baby bellied for the rest of her life. I guess she just REALLY wasn't into the gangbang scene.