A pack Brahman is in Preston Garvey's bedroom in Sanctuary. It's nighttime now in Sanctuary, and Preston is sleeping in his room. The beast completely blocks leaving the room. Maybe this situation solves the problem of Preston giving so many quests. He can't get out, so issue taken care of.

I can't figure out how to post a picture. I have a screenshot of this situation. I'd like to show it, but let your imagination be your guide.

Fritz

So, I guess, you never had them on the roofs. Oh, if you're short of some settlers it also pays to look up.

I don't know what it is with that game, but the roof is one of the favorite hangouts for settlers. Pack Brahmins go anywhere. You can only control the normal Brahmin population by building a trough.

Probably Carla's. If you fast travel to Sanctuary and she's already there, the Brahmin has a tendency to random spawn. I've had it on the roof of houses, inside houses, balanced on top of a turret and meshed into a generator.

You need to put up a sign that reads "no pets allowed"

Maybe he was, "lonely".

I'm more impressed by the fact that you built Preston a room.