I came across your company and thought perhaps you would be the persona that can help me.
I compete on the Professional Barbecue Circuit across the USA and I'm seeking to improve my pork category. I cook Boston Butts that are typically 9 lbs. I've been thinking of trying a piglet in the hopes it may be more tender and juicy. We smoke the butts for 8-9 hours. There is a rule that states all Pork Butts or pork shoulders must be a 5 lbs. This said, if I choose to cook a piglet, I'd probably have to cook the whole shoulder (butt & picnic).
I travel a lot and it's easier if I call you. Please let me know if there's a convenient time where I could give you a call.
I am not sure that I understand what you're asking, but I'll take a stab at it.
Most pork, including the shoulders that you are cooking, are from relatively young animals; usually 6 to 7 months old at slaughter. They're raised to a live weight of 250 to 280lbs and slaughtered.
The shoulder roasts you're cooking now are from animals that size.
You can eat a pig at any age; and many people do BBQ whole pigs; i sell a lot of 80lb to 120lb dressed weight pigs for that reason; any bigger and it's difficult to get the pig to cook through without the outside getting too dry or burnt. A lighter pig like that will result in smaller roasts, and I really haven't noticed a difference in taste & texture between them and the roasts on larger pigs of the same breed.
Random pork from normal retail outlets will tend to be either blue butts (a hybrid pig, hampshire x yorkshire) or a duroc based pig. They are popular with industry because they produce a large amount of lean pork and a favorable conversion ratio of feed to meet.
Pigs that have been popular with BBQ competitions are a different breed; take a look at the cochon555 competition, for instance. http://www.cochon555.com/
What people have been doing is picking breeds that aren't the usual lean pork choice, like berkshire, or red wattle, or mangalitsa, and by doing so they get a result that tastes better than the leaner pork than is common. My experience has been that people who haven't eaten heritage breed pork just don't know what they are missing, and after they've had a chance to taste what pork can taste like it's no comparison.
That's why i raise a berkshire-centered pig herd. I did so on the basis of a taste test when I was choosing animals to raise; berkshire pigs were the tastiest I was able to find, and that's held up.
It's easier for me to respond to email than phone; I have stuff I have to do, and email can be handled in the time between tasks. Plus it provides fodder for the blog.