I had a micro mini pig for about 1 year. I did 2 years of research on them before I picked a breeder and I talked to several owners and veterinarians.
Don't let anyone ever tell you that any pig will stay 15-20 lbs!!! Sorry but this is just not true!! Unless of course they have dwarfism or some other genetic abnormality that prevents them from being healthy.
The smallest pig that exists can get from 60-100 lbs fully grown. They sure are teacup when you bring them home at 6 weeks; Wilbur weighed 9 lbs at the age of 3 months.
When he was just over a year old; he weighed a healthy 55 lbs. He still had 2 years of growing to do.
Unfortunately people are breeding very young pigs and I am sure some of them have no idea that their pigs will continue to grow to 3 years of age so what you see are parents who are under 60 lbs and you assume they are full grown - they are not!!
Since breeders can charge up to $2500 per piglet - sometimes their visions of what is right for pig and owner are skewed.
I was fully prepared that I may have a 100 lb pig when Wilbur was fully grown - I also have the property for such a pet.
I must honestly say though that pigs gain a lot of weight in fat and width - Wilbur was no taller than my jack russell when he left for his new home.
Unfortunately it was Wilbur's fierce prey animal instincts that forced me to find him a new home as my pack of dogs were being very aggressive with him, I re-homed him to a pig only family for his safety.
In general, he was smart but he was not eager to please like a dog. He never peed where he slept but that didn't stop him from peeing in my house - no way. I was unable to let him have run of the house unless I was home to let him out frequently.
He drank a ton of water and returned it to my floors often. He was shy with strangers and god forbid you tried to make him to do anything he didn't want to do
You have never heard a scream until you have heard a pig screaming.
Wilbur walked with us on dog hikes and walked on a harness if we were in town. He loved to lay on my lap on the couch and would accept belly rubs for hours. He was good in the house - never destroyed anything but I also gave him as many natural rooting outlets as I could - esp if we were not home. He loved to be in a pile of blankets and slept on our bed between my feet. Sometimes if we had the bed to ourselves, he even laid his head on the pillow next to mine.
My nieces could not eat anything at my house unless they sat at the kitchen table, he would knock them over for their food.
Pigs are not for everyone for sure but if you don't mind a large, stubborn pet who will find food ANYWHERE and have a yard for grazing, sun bathing and making a mud pit - you would probably love one!!