The guys are right about not short changing yourself. Your time and knowledge are valuble. We do plate cost for everything we do. Some events we make a killing on and some we barely make enough for a PB & Jelly sandwich. But you have to pick and choose when your going to take a beating. The only way we do is if it leads to a bigger deal or it is a small one after a big one...... What a lot of people forget is the dry goods like plastic wrap, soap, spices, etc..... Figure out what you feel is a good food cost you can live with, we try to stay at 25%. Then labor and upkeep will come out of that. As for you raising your hogs yourself and selling them, make sure you have all of your ducks in a row with local food codes. Around here you would not be able to do that, it has to come from a USDA inspected vendor. If all is in line with that, the savings should mean more profit for you, not necessarily a savings for them. What happens if you quote a price months out based on your hogs and you have sold all of them? Now you are losing money.
I think that whoever charged the trailer cost is on point. It costs money and time for all of that, but on the other hand it also makes life a little easier having the kitchen right there.
Jeramy