Geese as Guardians?

This year, 2015, was our third year raising pastured poultry, and was far and away our worst year for predators. (Reading around, it seems a third year spike is a fairly common occurrence, as the predators have finally figured out there are tasty birds to be had.) We raise primarily heritage breed chickens for meat in portable pasture shelters, so they are on pasture for quite a long time, upwards of 15 weeks.

Prior to this year our primary predators were hawks and owls. The hawks would periodically attack the free-ranging birds during the day, and the owls would land next to the shelter at night, reaching in and grabbing (but not extracting) a bird. The occasional loss to a hawk I can live with as a trade-off for free-ranging. The owl attacks, which increased dramatically this year, can (and will) be largely dealt with by redesigning our shelters (which are wearing out anyway) to include roost bars, getting the birds off the ground and away from those sharp talons.

But this year we faced a new predator, something that attacked the free-ranging birds during the day, removing the chickens without a trace. There are neighboring dogs, but I've never seen them near the field with the birds, and anyway dogs tend to kill and leave a carcass. Not hawks, as hawk attacks leave a pile of feathers, if not most of the carcass. My best guess is a fox or two or three. I find fox footprints after a fresh snow, so I know they're around.

Anyway, all of this to ask: does anyone have any experience using geese as guardian animals for smaller poultry? Not just as loud, honking alarm-sounders, but as honest-to-goodness predator deterrents? Can we raise a few adult geese in a 5-acre pasture with chickens, ducks, and cows and expect them to ward off those daytime predators? Or is the goose just not up to the task?

I have a mixed flock of chickens, ducks, and geese that I range over ten or so acres. Our losses have been very minimal despite a healthy population of predators. (I only lost two chickens this year out of one hundred. Both missing with no signs.) And I've seen everything from wolves to wolverines on the property. So how much of this can I attribute to the geese? Well, I know for a fact that they will rush small predators, including our neighbor's poor barn cat!, who used to come around looking for voles. But it is all intimidation. In the end, a goose is just a goose, however brave, and no match for a desperate or determined predator. If nothing else, mine seem to keep the hawks at bay. And we always have hawks around. All in all, I would definitely recommend adding geese to your flock.

Adult Ganders are good for this but I wouldn't rely on just the geese in your situation.
While I have seen a Gander chase off dogs there is always a chance that the gander could loose the battle.
A LGD is always your best defense against things like foxes or coyotes.
Both would be excellent since, if they get along, the noise of the geese will alert the dog and there is nothing wrong with a good double team effort.
We have our dogs separated from the winged ones (our dogs love chicken dinner) so the geese are the first alert, these are in with the hogs and so far nothing has tested what our hogs would do to them.
The foxes don't bother since the dogs are here. We do have raccoons, cats, wild dogs, opossum that wander through when the persimmons are getting ripe but they came less this year than last.
One other method would be to use electric tape or electric net to deter any snooping four legs.

We have a large pack of coyotes in our area but they don't come up to our land for a few reasons.
1) when they do their gather up yips our dogs go off, barking like they want to eat some coyote for dinner. They bark even after the pack has rounded up and are on the run.
2) There are large cow pastures behind our land, we are on the end of the mountain range and fully wooded, the coyotes prefer to run the fields behind us.
3) If the pack should make the bad decision to check us out, I was Naval special warefare and I'm sniper trained, they don't stand a chance against my .308, and I'll leave the carcass so they know what happens if they come to our land.

The beauty of the goose is that it is a grazer, and therefore likely to be able to be self-sufficient on range. A flock of ten or more together is pretty intimidating to any single animal, but pack predators coming in groups will scatter them and cause losses. It will not be a quiet event though! Economically you would need to estimate the effectiveness of them as a deterrent or alarm, for minimal feed cost, versus the significant feed bill for maintaining a large LGD. On a fairly small, well fenced site, I think half a dozen geese could pretty much do what the average farm dog does, for a lot less, and, if something doesn't work out, makes a pretty decent curry!
Another thing to consider is a specialty market for young geese themselves, since they multiply easily. Geese are much better parents than most other poultry because most nests take place at the same time in the early spring, and once the goslings are more than a few days old, they mix up and the entire flock guards and parents them as a group. Individual babies rarely get lost and come to grief. With other poultry the babies all stay with their respective mothers and other birds are as likely to attack them as they are to help out. As an aside, when I was marketing to restaurants in Atlanta, several paid me $1 each for goose eggs! Apparently they are renowned for making certain fancy baked goods.

I wouldn't rely on geese to protect your other birds. We have had issues in the past during breeding season with the ganders attacking the cockerels and in one case killing my prize Andalusian cockerel. We also lost two geese to badgers so I don't think they would keep foxes at bay.

Some people use alpacas or llamas to protect sheep. It might be worth looking into whether they would do a similar job for poultry as they can certainly see off a fox.