(Chapter 7 case; after petition filed, debtor purchased cattle feed from creditor to feed cattle used in debtor's dairy business and such expense satisfied 11 U.S.C. Sec. 503(b)(1)(A) as an actual and necessary expense; creditor claimed that purchase amounts still owing were delivered during pendency of Chapter 12 case and involved transactions entered into in the ordinary course of business that qualified as an administrative expense; trustee objected; question of fact remained as to whether amount and extent of payment was consistent with past practice of parties; question of fact also existed concerning the large size of debtor's outstanding feed cost balance was consistent with ordinary course in the industry; as such, evidentiary hearing required on ordinary course of business requirement).