That's interesting, in this area, pairs usually list their bond in the first or second line of the description or share a listing. The ones that have their friends listed later on are usually groups of young pigs and say something like "would like to go home with one or more of her sisters" ... I think sometimes those pigs will be allowed to be adopted individually (to a new friend), since trios are probably harder to home all together.
I do find that some of the newer animals have very little description, probably because they get them listed as soon as they're vet checked but don't necessarily have the picture and/or description ready, or the description just says something like "we don't know much about this pig because the previous owner told us nothing," and then it might get updated to include what they learn. All the shelters I've looked at have an age approximation.
Of course, I find the descriptions aren't always accurate anyways ... Lexa was described as "likes parsley, doesn't like cilantro, peppers, or pellets" ... doesn't like cilantro was right, but she loves pellets and peppers ... not very keen on parsley ... guess it was better than the cilantro, lol. Latte's shelter thought she could only be held for about a minute and were shocked when I was able to hold her through an entire conversation with them. (I did have to retrieve her from my shoulder initially, but she settled down nicely.) They told me she didn't like her greens ... but that was because she didn't like their greens, which appeared to be what we would call spring mix (frisée, arugula/rocket, baby spinach, red leaf); she loves romaine. Her age was off by several months, too, based on her size, nails, and subsequent growth.