The answer to your question depends on many factors and is really a decision that if not governed by the state is a decision that is made locally. I am attaching a link to an article on the recent changes in Michigan's Right To Farm Act Siting Selection Criteria GAAMPS which includes some detail on a Category 4 site (part of which includes your question on the 250 feet - but not exclusively).
http://msue.anr.msu.edu/news/new_right_to_farm_act_siting_gaamp_now_in_effect
Included in this article are several other references that you may want to look at to help answer other questions to raising livestock in Michigan.