Wyo. Stat. § 34-4-103

(a) To entitle any party to give a notice as hereinafter
prescribed and to make such foreclosure, it is requisite:

          (i) That some default in a condition of such mortgage
has occurred by which the power to sell became operative;

          (ii) That no suit or proceeding has been instituted
at law to recover the debt then remaining secured by such
mortgage, or any part thereof, or if any suit or proceeding has
been instituted, that the same has been discontinued, or that an
execution upon the judgment rendered therein has been returned
unsatisfied in whole or in part;

          (iii) That the mortgage containing the power of sale
has been duly recorded; and if it has been assigned, that all
assignments have been recorded; and

          (iv) That written notice of intent to foreclose the
mortgage by advertisement and sale has been served upon the
record owner, and the person in possession of the mortgaged
premises if different than the record owner, by certified mail
with return receipt, mailed to the last known address of the
record owner and the person in possession at least ten (10) days
before commencement of publication of notice of sale. Proof of
compliance with this subsection shall be by affidavit.