I cannot confirm or deny whether Kobolds are breeding. Every time I get a camp running either I update the raws or I get a dwarven siege or something. I will look into the matter.
On a side note, how the eff do you have camps going for 8+ years!?
I basically cheesed it with cage traps. They still work, they're still overpowered. You just make a closed off tunnel the enemy has to go through (either tunneling a single entrance, or as I do, make a wood wall perimeter with a hallway entrance, and sieges walk right into it.
It sucks the !!FUN!! right out of kobold camp, and much of the spirit too, but I did want to test a lengthier camp to see how it went, and discover issues like lack of marriage.
That, and also another apparent issue in that my kobolds seemed to refuse to put on new leather ankle bands after the original footwear decayed into nothing. They can't seem to make regular shoes, either. I had one or two getting dangerously close to going berserk or something because, despite legendary meals and decent quarters/other stuff, "Has been disturbed by flies" and "Has been embarrassed by getting caught without shoes (x16)" was just too much. With said cage traps and a highly prolific food market, it seemed like my kobolds had nothing to do but brutally mock each other for lack of shoes without shoes themselves.
If that fort was going to fall, it wasn't going to be from a powerful dwarven siege, it was going to be because of kobolds going insane from lack of shoes.
Another discovery is that prepared foods are an amazingly lucrative market (or rather, extremely lucrative compared to the bold's other markets). At least 95% of my created wealth (1.5 million after 10 years when I retired it) was created by a small team of legendary cooks. Doesn't really need to be changed, I don't think, it just does make a kobold camp far more wealthier than it has business being. With this stuff, though, I was able to purchase steel equipment from my kobold civilization - this is probably not ideal since this implies they have some kind of metalworking department at home, but trying to fix that without breaking other stuff is probably pretty tough. Maybe. If it were fixed/changed though, it'd be harder to stop goblins from trading, at the least, good shields/weapons, since those are one size fits all. Anyway, once it was said and done, 5 (well trained) kobolds were enough to trash an elvish ambush of 5-10. I don't know how well they would have done against a dwarven siege; probably not that well, but I haven't had a chance to test it out.
And lastly, adventure mode seems interesting - I can actually talk to people and kobolds, kobolds seem to have shops (I'm figuring cities for kobolds are still in) and it generally works way better than I expected it to, kobolds and all. I mean, I still die from a stiff breeze, but that's how a kobold do. That, and I also could not equip a leather ankle band, nor a steel cap, which I found in my retired fort. I didn't find a steel shinguard to try on, but I didn't look long either, as wandering around a player made fort makes for a terribly laggy experience.