I like the mini fridge, sink, & mini kitchen area. for the wee apartment. Some place to catch a couple hours' sleep between bottle feedings or when expecting a cria. Or if the weather sucks, to not have to trek from the house any more than necessary.
It is ideal to have enough space so each of your child has its own bedroom. But what if you have just one bedroom and four kids? The best way out is opting for bunk beds that will accomodate all of your kids plus will help solving space issues.