Ok, the easiest way to get gold/best time on this level is like this:
Immediately sell 4 pigs. Upgrade your warehouse all the way and as soon as the car gets back, upgrade your car once, and your well once. Buy 10 styrofoam trays and 1 flour. Buy one chicken. Process the meat as you get it. Once you have your egg, sell your chicken with whatever packaged bacon you may have. Buy 15 more styrofoam trays.
Keep collecting/processing everything. Once you have about 6 packaged bacon, sell your cake, your packaged bacon and 4 more pigs. Keep collecting/processing. As soon as you have enough packaged bacon to make $10,000 when you sell it, sell the bacon. Keep the pigs until after you have the cow. Once you have the cow, sell the pigs with whatever packaged bacon you have available, and keep processing your meat. You should wind up with enough meat products to sell that with the first one or two jugs of milk you have enough for a second cow. At this point you should just have to keep feeding your cows/collecting the milk. I just finished in 5:21