Slavery and the Economy in T2k

[B.T.]

Right at the moment I'm working out an adventure for my FtF-group. During our last session we had an encounter with a group of slavers. The slavers were on horseback and had disguised themselves as ordinary merchants (Which, by the way is odd: How can anyone clearly spot the difference between traders and slavers, if the slavers have no slaves with them, anyway!?). It was a group of 5 persons with six horses. Because of the things happening, I thought, a group of slavers would not have slaves with them. I imagine, these 5 guys are some kind of scouts, checking for an easily to capture group of civilians, they could lay their hands on in the next few days. These 5 persons are propably a small patrol, belonging to a much bigger group, someplace in the area. The encounter had been roled for, as described in the basic rules.

Now, I can see, that slavers play a role in the economy of the T2k-universe, but there are some questions to bear in mind.

Slavers will not roam the countryside and capture anyone, who encounters them (Well, some would, but I doubt, that those would be very succesful!). Slavery is a risky business. You need some buyer, who is interested in using slave-labourers. And it makes no sense, to search for victims, if you had to transport those slaves over a longer distance.
If you have slaves to transport, you will have to feed them. If you don't, the price would be minimized. I think, this is the logic behind it: Slaves are intended to do hard labour - if they are in a bad shape, it is not a good idea, to buy them: They are to weak and can't cope with their tasks. The better the physical shape of a slave is, the higher the price, you will get for them.

I can imagine, that slavery would be some kind of "business on demand": The employer of slaves (Mostly a very nasty bastard, who might be the commander of a marauder force or a ruthless criminal, who got his hands on an old coal-mine or something similar.) would pay "slavers" for a specific hunt. This could be something like: "I need 20 to 25 strong individuals, fit for hard labour. These have to be here in about 10 to 14 days. I'm not going to pay for children or disabled."

So, the head of the slavers will have to do some economic math:
How many slaves may be transported, and by what means? Usually slaves would be tied up and walking by foot. Still some transport would be used for food, water and minimal shelter for the slavers.
How much food and water is required?
How many slaves can be handled with how many slavers? You have to guard your goods (= slaves), you will need some kind of scouting unit, to check/clear the way and you will need more guards, if the party stops for a night - ordinary guards, guarding the camp, and some people, who have a look after the captives!
And you should better have some heavy weapons with you, if you encounter some policing force or a kind of posse! Ammo and the weapons themselves have to be transported.
What would be the travelling speed of a slave chaingang? Does such a group make more than 10 to 15 km a day in a wooded region.
How is dealt with the personal hygiene/lavatory needs of the slaves???

Keeping all that in mind: How can the price of a slave be determined? Is he worth the price of an oxen or an uncattled horse? Would that be to expensive and the price for a slave less?
Would a slaver be in the mood to sell his goods to a bidder, who just wants to free the slaves? How could the price be calculated in that case?

As you can see, this thing is quite complicated. I could use some thoughts and suggestions. How have you dealt with slavers and slave economy in your adventures? And what is your opinion on this whole affair?