They don't migrate in the typical sense, but they certainly change high use areas and patterns throughout the year.
Hoof rot has impacted nearly every westside elk unit in the state. In 501 specifically however, I believe a much bigger factor is the amount of logging that has taken place in the last 15 years. ALOT of state land has been logged in country that historically provided much needed protective cover, couple that with an antlerless gun season and its a big impact. I know of several big clearcut shoot outs that put a whooping on them.