Tractor Supply 3rd-Quarter Earnings Drop  NEW YORK (Reuters) - Farming supply retailer Tractor Supply  Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=TSCO.O target=/stocks/quickinfo/fullquote"&gt;TSCO.O&lt;/A&gt; on Monday reported that its earnings fell in the  third quarter because of higher freight costs, higher costs for  steel and other commodities and a shift in sales to lower  margin hurricane-related items.