It sounds like normal dominance behavior to me. It's good to have doubles of food/water/hideys so that no one pig is denied access to the necessities. It's also possible that Calico is experiencing some hormones or is in heat, which can provoke more noticeable dominance behaviors, more so in some pigs than others. If it's hormonal, it should settle down again within a few days. Hormonal behavior is more noticeable in some pigs than others, and may be stronger in some seasons than others.