My boss at the grooming shop where I work has three dogs. Alice, her 1 year old as of a few days ago, Shih-tzu X chihuahua, is causing the problem. She's been through some changes recently...I think it was about four months ago when my bosses older dog, April (13 yr. shih) had a seizure and spent a few days at the vet. Since then, Alice has been even more attached to her, cries if they're separated, runs up to check on her as soon as she gets back into the room with April. About two months ago, my boss also added a 4 year old whippet to her family. All three of my bosses dogs sleep under the desk during the day. Recently, and it only happens sometimes, when a dog walks past the area where Xena and April are sleeping, Alice will go after them, snapping and snarling. If this behavior worsens, it means Alice will have to stay in the other room (we have two rooms), away from her "sisters" all day. I'm not sure how to approach this. It's obviously not an anxiety issue or anything, I'm thinking it's a "protective" issue, or just her age, really. So far, we've been praising and rewarding Alice whenever another dog goes in the area and she doesn't react, to associate other dogs being there as a good thing. If she gets really snarky, we ask her to move to the middle of the room, or bring her into the back for a little while. Some dog trainer told my boss she has to yell at Alice when she does that. I don't think that's right, but we have been saying "NO!" if we catch her in the act, I don't know if that's a good thing to do, though. So, any advice or help would be good here.