One year old is hitting

He started about two weeks ago. This was at the exact time that he got move to "the big boy room" at daycare. He does not get it from us, we hardly even raise our voices around him (until recently, see below). He has turned from a loveable, playful, sweet boy into a terror who hits ALL the time. If you hold his arm to stop him he flips out. Look at him sternly and say no and you get another smack across the face. The only thing that works is a quick and loud "No!", but I don't want to yell at a one year old. My wife dropped him off today at daycare and saw another boy hitting other kids. We are almost certain this is where he is getting it from. The daycare likely won't take action if they haven't already, and they can't stand over the hitter (instigator) at all times. What do I do? All of the online guides give advice that is only applicable if the child is not exposed to hitting by siblings or outside sources (i.e. the ability to remove him from the influence). via /r/Parenting http://ift.tt/2nntg5g