Employees believe the devices used to warm baby chickens may have caused the Saturday night fire.
Assistant manager Richard Irvine told The Coos Bay World the fire damaged everything inside the Milk-E-Way Feed and Trucking store.
The cause is still under investigation.
The blaze was limited to the store, leaving storage buildings on the property undamaged.
Despite the loss, owner David Sclery and his employees continued to serve customers Sunday, selling hay, seed, wire and other supplies that weren't damaged in the fire. Irvine says the business, will remain open with regular business hours as repairs are made.
Information from: The World
Copyright 2013 The Associated Press.