Many fence designs are available, but the kind that's suitable depends upon the size of the area to be protected. An 8-foot angled, wire fence or an electric fence may be needed to keep deer out of large lawns, gardens, and fields. A 4- to 6-foot fence or snow fence is often sufficient to protect a garden patch because deer are reluctant to enter small enclosed spaces. Two-foot chicken wire or other small-meshed fencing will deter rabbits, but the fence should be set a few inches into the ground to keep the rabbits from digging underneath. If both deer and rabbits are a problem you can fasten the chicken wire to the posts that support the deer fence.

Fences are the best way to deter deer and rabbits, but they do not provide 100 percent security. Inspect and repair the fence or barrier frequently and, if necessary, take additional control measures.

Here are links to more information:

Deer-Coping
Controlling Deer Damage in Missouri
Effective Deer Fences
Controlling Nuisance: Cottontail Rabbits