Are they having trouble accessing the beds for some reason? Do you have steps going into the house?
I built a bunkhouse on the west side of the main house and they have no problem going to bed. There's even a trading post and guard post along their path. Make sure the steps are stutter free when you walk up them and that the beds have good spacing.
Those damn tatos! I wish we could scrap or store them and just plant new ones!