I recently adopted 3 sows maybe about 4 or 5 weeks ago? One of the new girls seems to be OBSESSED with smelling/sniffing my OG (desexed) boar's mouth. He seems to tolerate it and I've seen him groom her occasionally. At times, she is so intent she will stand on the bowl's edge to be able to get high enough to get up in there! I would estimate her age to be approx. one to two years old. They all eat the same food so not sure if this is it, however, it mostly occurs during food time.
Does anyone have any insights into this adorable behaviour?
Meanwhile, I suggest you do a little mouth sniffing (for comparison) to see if there happens to be any particular odor emanating from your boar's mouth. Could be an abscess or pockets of fermented food in the mouth?
Other than these few ideas, it may just be an unusual behavior.