In Texas, raising blackbuck behind short fence happens pretty regularly, but you will find the odd animal that heads to other parts via a good jump. This is especially true if the animal is harassed while standing next to the fence. Where you really have to be careful is with them going UNDER the fence. They will wriggle through even a small gap. Several of the sheep species and most of the other small antelope species can also be raised to some degree of success behind a short fence, but it bettr be a darned good fence.
Yes you can keep them behind a 4' fence but it a relatively bad idea. For the cost and labor to put up the material you will need to also keep the coyotes out, you can almost put up a full high fence. If your wire is more than 3" apart, the blackbuck baby's can get through it and so can the coyotes. If you have bad coyote problems, then your blackbucks will have a poor chance at survival. They can wreck havoc on the babies and the mothers. There isn't much a problem on the males since they are hard horned and can defend themselves better.
Rather than spend my hard earned pennies on those cool Shoot-N-See targets or even the preprinted targets at sporting goods stores, I save a few bucks for weekend plinking sessions by using paper plates as targets. A 100 count pack of paper plates costs less than a 10 count pack of preprinted targets.
If you are playing with something like a semi auto AK, or building a young shooters confidence with a 22 or shotgun, those big eight inch blanks are perfect for putting holes in all...