We have two Maremma's. We got our first one almost 18 months ago, he was 5 months at the time. We added a second one 9 months ago. We only have 2 1/2 acres and that includes our house, yard, etc. We have 3 1/4-1/2 pastures that rotate our goats and geese/ducks through. The dogs live with the goats. The pastures are in a L shape, the chickens, turkeys, rabbits, etc are all in the barn and coops inside the L shape. Since the day we brought home our first dog, we have not lost one animal to a predator. Before that we lost numerous to fox, raccoons, stray dogs, etc. Our male was being a bit to puppyish with the goats, chasing them and such so we took him back to the breeder who worked with him for a couple of week. Mainly putting him in with a couple of adult trainer dogs, who wouldn't put up with that. We also purchased a second pup for him to play with, instead of the goats. It worked, he has been a perfect gentleman since. Now the second pup is going through that stage, but I know it wont last, with time and training, she too, with outgrow this stage.
I do not brush the dogs everyday, but do have to brush them out periodically. They do get mats but we have a lot of mud, so that doesn't help. I am lucky, my dogs don't even try to get out of our pastures and I know they easily could. I know people have used other non traditional breeds for guarding their poultry or other animals, but why? LGD's were develop and bred for hundreds of years for this very job! You wouldn't use a chihuahua as a schutzhund dog or a pair of shih tzu's to pull your dog sled. If you already have the dogs and they turn out to be great, awesome, you are ahead of the game. But you are much likely to have problems, especially long term ones with a breed that has been selectively bred for this very thing for many, many generations.