The largest number that I know of being caught in one of the circle traps is 5. I think it could depend more on which feral group, sow with piglets or boars for example. once they are in the trap you could just dispatch them on the spot or you could capture and remove them one at a time for dispatching. I would much prefer to be able to use their meat than to just let them rot so I am in the process of learning all I can about best methods for cleaning and proper precautions to take in order to not catch any of the myriad of diseases they can carry.
My wife and I have plans to raise one pig per year on our farm for the sole purpose of making meat and pork fat. We have plenty of acorns, hickory nuts for this one pig to eat, this will make the flesh very tasty and not anything like you could find in a supermarket. More like the Serrano ham of Spain is what we will be shooting for.
We will not have cattle ever, they are not in our plans because we firstly don't have the space they would need, secondly we could never use all the milk a dairy cow would produce and third we don't eat that much red meat. We eat, chicken, rabbit, goat, guinea, duck and fish for most of our meat needs. We do have friends that raise grass fed cattle and we trade for any beef that we need for our diet.