For the past 2 years we have kept 3 pigs and shared the cost of them and looking after them with our friends. At slaughter time, we each get 1 1/2 pigs - perfect for each family (we eat a lot of pork!!). We have now expanded this philosophy to cattle, and share 3 highland cattle with our friends - we have just had one back from slaughter (shared it out again) and the beef is FANTASTIC!!
This system works for us, I believe, because we keep it small - just us and one other family. Other people have asked if they can join in and I have politely declined, only because I think it could get messy and difficult to manage. However, if you had the time to devote to it and oodles of land, it could be something you could successfully expand. Good Luck!