I do believe that animals can sense many things we cannot. This sure sounds mysterious! At my school, a few people believe part of the school is haunted. There have been incidences of pencils rolling across tables by themselves, doors opening and closing by themselves, footsteps above the ceiling, where there is a room nobody has been in for years, mysterious noises that sound like moaning coming from certain rooms, and generally people feeling chilly or sensing presences, and I've experienced some of these. Maybe there are explanations ,but it sure is spooky!