You really dont need a fancy breed of dog to protect your property. Most muts will willing do the work and love it. Since you only have an acre it will be easy for them
My dog guards about 4 acres of our 8 acre parce but he will keep deer off the full eight becasue he can hear or see them from afar. I can count on him to keep fox, coyotes and deer away from my garden beds that I have relatively close to the house. My gardens further away we did fence for deer for he cant guard them well from the area he likes the best and rabbit were the biggest issue out there.
He keeps deer out of our pasture and runs foxes off. Ive never seen a coyote on our land and perhaps its because he marks the perimeters routinely, but there are coyote all around us, and some wolf too.
Scent will keep some animals at bay.
What he has not done so well with is skunks. They just kind of ignore him. Rabits tend to keep their distance but I see them around once in a while. I put 2.5 foot fencing around a couple of gardens that were close in for them but Im not sure that I needed to.
Our dog was raised from a pup and he's half chow and half golden lab... he looks more like chow in his black tongue and thick dark fur and curled tail but his snout looks more like a lab and his demeanor is more like lab with people but he will get all gruff and bark at strangers. He's never bitten anyone and really if someone wanted to rob us this dog would not keep them away for an extended hand and a freindly voice is all that is requried to lower his dander.
So you really dont have to have a fancy breed. Id go to the pound and look for a dog that is half guard dog type and half hunter type and a pup or young dog is best. Walk the property with him and let him know what is yours and what is not. Many dogs can be good protectors without paying through the nose for a pedigree. It is instincutal for them.
If I had chickens I would not count on the dog to protect them at night. You will have to put them away in a secured area that a fox cannot burrow into. Burying the fence down 6 inches helps or actually fencing the bottom of the cage, then cover with soil, hay, whatever. Our concern here is attack from bald and golden eagles in the pasture. I dont have chickens yet but if I free range them i might have to get a different dog to train to stay with the chickens in the pasture all day long. Our current dog is too old to learn new tricks.
A working dog can be worth their weight in gold. Mine didnt start out that way but he has risen to the task when we moved from the city to the country.