Ah yes, my stone is better than your stone and your not having it.
I noticed on the unit That I worked on it was maybe 3 or 4 sows with stones they had
Found ,sometimes they could be quite possessive over them,always amusing to see them put them down when they
Entered the feeders then collecting them up as they left.
I was told that it was a way of stimulating the production of saliva.
Anyway better the sows running about with a stone than causing mayhem with an old sleeper or tractor tyre
In this shed !