What I mean is this is the first major measurable difference we have noticed between the lop-eared (GOS and GOS x OSB) pigs that we have kept previously as against our tamworth x large whites this year.

We use the electric white tape for our pig enclosure. As the pigs get bigger I move the fence back so they get more area to rootle around.
The lop-eared pigs would not cross the original fence line for at least 24 hours after I moved the electric tape. They would come right up (as in millimetre perfect) to the original line, but no further - even if I tried to coax them over with treats. They would eventually pluck up the courage after 24 hours or so. This would happen each time I moved the tape.
At the weekend I expanded the pig paddock for our prick eared pigs - as soon as I moved the tape clear of some juicy looking grass the piggies were in and chomping! They established to new perimeter position immediately, without having to 'test' the fence. So, from my experience I would reckon that proves they use their eyesight to a far greater degree
