Duckfarmerpa1
Herd Master
Oh..geez...It varies but generally speaking they sleep where the animals are. Some will come into the house for a bit but won't spend the night away from their charges. If you lock the animals in the barn at night, you might need a door for the LGD. Things might not go well if it can't get out to the fenceline to warn off what it hears. You don't want the dog frustrated or ripping at the doors to get out.
Given you have other dogs, you might need to keep them out of where the animals are if you get an LGD, it will quite possibly consider them a threat to the guarded animals.