Hi
In chat I've heard a CSR saying that an identical twin in a more rare event comes than an unidentical twin.
I breed since 2011 and just recently I've got my very first twin and it was unidentical.
While it is one of the most rare events to receive a twin I have no clue what the market for them does.
I think it has the correct value for the right buyer.
I think the best thing to do is asking yourself what you would be willing to pay for the twin and price them occordingly.
I've never obtained a twin on the market because they do not give extra breeding benefits stronger even once unboxed there is no way to tell anymore that they used to be twins.
Since I've received my own twin, which I rather liked, I keep them boxed as a memory of this rare event.
Perhaps by pricing them the traits should be taken in consideration plus some extra value because they are twins.
Best of luck with selling them! :-)
~ Kay