I was annoyed when looking at Erikson's Wolfs & Hounds trying to fit in doghouses,
But I see them sleep in Far Harbor, on the floor, so I've used the markers on daisy rugs, and now we have craftable markers for them to sleep.
- Workshop dog rugs are located in the same menu than the doghouse.
- They will sleep on the rugs form 21 to 6 (9pm to 6am), at daylight they will refuse to sleep, but they will be (probably) near to the rug.
- At the sleep period, if you "talk" to them, they will wake up for a momment, and then they will back to sleep.
Note: To get it properly working you must remove any current doghouse you have already placed and then place a rug for the type of dog (wolf / hound) 
that you have in your settlement, then you can put the doghouse if you want.

NEW: Added a plugin that let you use the rugs in "Home Decoration - Daisy Rugs" as dog sleeping rugs.