If there is EVER a smell, other than a certain 'ratiness', with FT you should chuck it and get new. When frozen they should smell cold and when thawed they should smell like a clean rat.

As for thawing, I do mine in a tupperware container in hot water shortly before feeding...usually while pre-scenting those who don't take FT. For mice and rat pups it takes about 5-10 minutes, and for medium adult rats it takes about 30 minutes for a good complete thaw. RIGHT before offering I blast em with the hair dryer so they're good and warm.

Right now I get my FT from Colorado Rocky Mountain Rodents. They're nearby, the owner is a sweet woman, the prices are the most reasonable I saw (and I go nutes comparison shopping), and the packaging is great.

Most frozen rodent orders are shipped priority or even overnight in an insulated box with dry ice. I have an arrangement with my supplier and the ladies in the apartment office that the UPS man should leave the box at the office. They keep it in a cool room until I get home.