So I have been reading up about probiotics mainly because Merlin has a fairly sensitive stomach and I was hoping it would help. I have started him on purina Fortiflora and all was fine, however today (3 days in) he has shown increased nervousness. He has spooked at me moving a book, the ironing board, my own boots walking, and his agility tunnel. He has always been a nervous dog at times, but never this skittish. I am wondering if they could be connected? I am also wondering if anyone has some probiotics they would recommend, as I have subsequently read a few articles that suggest Fortiflora is not great even if it hasn't caused his nerves to be shot!