I think they are only in the tack room overnight; they are running about the holding all day, according to the opening post.
But that's contributing to the problem. They are allowed to run about at liberty, making their own entertainment (which seems to mean chasing all the other inhabitants) all day long, then locked up with nothing exciting to look at all night. Of course they bark.
They need some structure, some training, some interaction with you or other humans. Dogs which get exercised, are made to think, do work, are happy to sleep at night. Even if outside. (My collie dogs, like many farm collies, slept in a stable when I was farming up north. They would have an evening howl, chatting to the other farm collies within earshot, for a few minutes late evening, and then not a peep all night unless there was something to bark at.)
They also need periods of down time during the day.
If they were mine, they would get a nice walk before breakfast. (Not let out to run about on their own, taken for a walk. With interaction with the human.) Breakfast and snooze time while I have my breakfast.
Then maybe have a couple at a time accompany me as I do my jobs. Maintaining interaction, any dog which stops interacting with me and / or starts chasing livestock gets switched out for one of the others. No dog which is barking gets brought out, only quiet dogs get brought out. (I might have to take opportunities quickly to get all the dogs out, but there needs to be no reward, ever, for barking for attention.) As they are all used to being uncontrolled hoodlums for 12+ hours a day, there may need to be a transition period; I may need to have them leashed (to me to keep my hands free, if nexessary!) while I do my jobs for the first week or two.
Nice walk all together, maintaining interaction, downtime.
Bit of training or play or grooming or practically anything as long as it's a bit different (ie., not the same thing every day) and they are interacting with / listening to me - and not chasing livestock. Bit more downtime.
Walk before or after supper as suits my regime, bedtime.
If they have had their brains stimulated, and have had some downtime during the day, they should sleep much better at night.
Gradually, I would expect to be able to let them have some more freedom while I have them out with me during the day, and eventually I may be able to let them all be loose and unsupervised for short periods. But you want your dog(s) to want to be with you, not entertaining themselves. More than 2 dogs entertaining themselves is a pack and will eventually hunt.