Do you mean those who ran away during the night? I don't think so, the game literally treats them as they were dead.
As far as I remember the only slaves you can get back, once they have left your mansion (apart from Emily and Cali, of course), are those that you have sold: they should still be available on the market for a few days.
4 days to change eye color. I can create an entire reproductive system in 1 day and the patient will recover that same day.
Making an exquisite doll really isn't worth it, not unless you're a Slaver making twice the payout. You could probably keep a couple of them in development, more efficiently than I've done this one. I feel like I'm leaving the job unfinished, but I suppose total objectification is the job.
The player character menu could use some more features. Not being able to change your hairstyle or body picture can be worked around, but not being able to cast heal on the only character you have to take into combat is just obnoxious.
How do they fuck? Positions matter. If I am not mistaken, when you spit-roast a slave, the pussy/ass is yours, while the other man/futa/beast fucks her in her mouth. When you double penetrate a slave, the pussy is yours again, while the ass is for your companion.
That said, actually I don't even know if dogs/horses can impregnate a slave, I trust enkephalin07.
Have you played the tutorial? First, progress into the main quest (you must join the Mage Order); then, inspect a slave and click "Customization".
Slavery is a widely common occurrence in the world, and has been implemented in nearly every region in one form or another. Slaves are generally used for small tasks and as valuable sources of mana for mages. With food production being poor, and its distribution unreliable, keeping a significant number of slaves around seems almost like a luxury, although in more prosperous regions it's not uncommon for middle class people to buy one or two servants for personal use.
The Order of Magi regulates the practice of slavery and tracks possible escapees; as in the past, slaves played a massive role in magical experiments. Branding is what defines a slave, but branding may only be performed by either members of The Order or the Slavers’ Guild. The Order keeps track of every local member's marks so that their slaves have no problem being recognized. However, anyone in possession of a slave not belonging to The Order (such as when buying from the guild) must register his slave and brand to prevent his newly acquired property from being taken away. Unidentified slaves are considered to be the guild's property and are generally used for various social assignments and sometimes end up being released after diligent service; eventually even making a considerable career.
While owners possess nearly unlimited control over their slaves, they are also expected to keep them fed and sheltered, making it a valid option for poor people to sell themselves into slavery, provided that they are attractive or useful enough to be taken. However it's not acceptable to forcibly enslave locals without agreement from their relatives, and doing so results in a penalty. Relatives are also able to buy out such slaves, but not for a lesser amount than what was paid, which holds true even for non-locals.
Given the nature of laws, exotic or high quality slaves are often taken by individuals raiding other regions and trafficking captured people for sale. Some mages went a bit further and employed personal portals for easy access to fresh candidates for their experiments.