I haven't done it with hops, but I would think they would be fine to cut in half with an axe or even a pruning saw. If you can cut a rhizome (off a crown), and it grows, I don't see why splitting a crown would kill it.
I have done it with hosta crowns (axe split) and you end up with two plants..
-Those that know donít close the door on those that donít know (The Gourds, "Education Song")...
-The brewer's yeast ferments, and forgives, all that you did...(The Gourds, "Right in the Head")...