Hey babsbag I like your fence structure and design, my neighbor uses that some plan and it works well for him in managing the livestock and keeping out predators.
It depends on the feed, off course there's pig food that won't be good for goats, but again there is some food that would be suitable for other animals besides pigs.
My advice would be that you check the ingredients to see if they are any that won't be suitable for goats in the pigs feed.