With current prices of the other ingredients there would be about $40 of additional feed cost to take a pig to 270 lbs.

A pig going on feed right now is gonna be sold in late Dec early Jan so if you wanna hedge them its gonna be on Feb which as of now is at $80.67

That 270 pig is gonna have ~ a 200lb carcass so you're gonna cash a check of ~$160/hd without any basis.    The basis in Jan vs the Feb contract can be wild and there is very little you can do about it with live animals that don't store very well.   In Jan the basis could knock $5 off the price = $10/hd so your check would only be $150

So you've got $150 - $120 for feed, leaving $30 for everything else.   Pig purchase price, labor, building payment, electric, water, propane, vet bills, death loss,etc

If you're paying someone to feed those pigs for you that alone will take $20.    If you lose many hd of big hogs that have eaten $100 worth of feed death loss can be a killer.  

The value of the manure varies a lot but after paying for pumping its only worth $2 maybe $3/hd.     On a lot of hd it adds up but not nearly as fast as the feed bill does.    It seems like the cost of pumping goes up every year.