I have two sheps that always used to bark on the last loo before bed, i have taught them quiet which they now seem to know the sound and after a few times its stopped them barking last thing, i always say quiet before i open door and now seem to know its part of the routine , though i still say it every night, i think they can hear what we cant and are just protecting there ground, its the same thing every night , lol, it goes Go wee wee then quiet and i dont have a problem with them at all now, i used to drag them back in which they didnt understand , until someone on here said to try this and it worked,