Life in the Shelters is hard and thus most of the population is young. We needed to put these girls under special guard, since they're constantly hungry for sex - a commodity their malnourished male counterparts cannot provide in enough abundance. We can perhaps make use of this by pimping them - training them to become Maids will be a challenge due to how utterly useless and weak they are, not to mention sickly. Both these career paths, however, would be a heaven in comparison to the conditions of a Shelter.