My husband and I have a large garden every year that produces veggies like crazy. (A friend calls our back yard "the Napa Valley of Maine" because the garden does so well.) The one problem is with or corn crop: Wild turkeys come through and knock all the corn stalks over just before the corn is ripe enough to pick so that we only get short, half-ripe corn. My husband insists he just needs to make a better fence, but they fly right over the top of the existing one. All the "normal" stuff used for keeping wildlife out of the garden doesn't seem to faze these birds. (These guys are so bold that they tried to face down my daughter last year when she went out to shoo them out of the garden with a broom. The biggest tom turkey got whacked with the broom when he refused to back down, which finally startled the rest into running - and I wish I'd had the video camera handy to catch the action for America's Funniest Videos... lol)

Does anyone have hints on how to keep the turkeys out without forcing my daughter into 24 hour per day sentry duty?

Hi,
I live in VA, in the Appalachain Mountains, with plenty of wild turkeys. I do not have experience in something that will keep them away. I do know that anything that works with wild geese (have some of them, too) will work for turkeys.
Here is a link:
5 non-harmful ways to control Canada geese on lawns, golf courses, and atheletic fields

These windmills listed in the link above might just do the trick. I do know that keeping birds out of fruit trees is an art. I use to hang aluminum strips in Peach trees, keeping out Mocking Birds and others, who love fruit. It works.
Motion with flashing sunlight reflections will scare away birds.
If you do some research on the web, there are also Turkey repellents that are sold. Although I've never used them, they might work. Best of luck.
A friend down the road has a high fence (about 6 feet) around her corn, and it does help some, but doesn't keep them all out.

Will those plastic owls mounted on the top of the fence intimidate them at all. I really don't know but thought it might be worth a try.

I have a backyard vineyard with about forty vines. One year they stripped the vines clean. Now the only thing that keeps the turkeys out is bird netting -- all over. I built a cage for the netting with posts and rope, as they will just push netting up to the fruit and eat it through the netting if you just drape the nets over the vines. Their latest trick this year is to jump on top of the netting and break the ropes and posts so the net drops down to the fruit zone and they eat he fruit through the netting. So now I have stronger rope and post supports. Stringing a wire about 12 inches above the top of your fence may discourage them, because they like to get onto the fence and look around before jumping into your yard -- and eating your fruit and veggies. Yes, they are vicious and have strong claws, so be careful about getting close to them.