Its kind of easy to tell the difference the boars are brown with black vertical stripes, called bars.
A bar hog (or barrow) is a male hog with his testicles removed.
There is no such thing as a true russian boar, most of the the "russians" in the states are hybrids.
A feral hog will revert back towards looking like his wilder cousin the eur-asian boar, but you can still tell the difference