Yeah, it kind of feels like each episode drags on a little bit. But then they have this crazy cliffhanger at the end and I''m dying to know what happens on the next episode!
I think he keeps them in the barn because he still thinks they are people with souls. As a man of god and being so secluded their farm, they don't realize what terrible killers they are. All he knows is that they are members of his family and friends and that there must be a cure for this "sickness" eventually.
And honestly, by now, even I would have given up looking for that girl...