Just something I'll throw out there....First, I agree with what others have said about kids and dogs (my kids were little when we adopted our first hound and our first hound had some issues so I know what it's like trying to keep everyone safe). Secondly, is it possible your dog has issues (space, sleep aggression, ???) that may just now be coming out? Maybe in the past when Lizzie stepped on her she tolerated it but now she feels more comfy letting you know she doesn't want to be stepped on or she's scared of being stepped on. We have a new hound (Had him about 2 months) and he barked at my 18 year old for just sitting near his bed (I was in the room and witnessed it - my son did nothing, just sitting on the floor, near the bed, texting on his phone.) He has never done this before so I wonder if he just feels more comfortable now letting us know he does't want us that close when in his bed. Anyway, sounds like you have a nice dog and I commend you for trying to work this out but for the sake of hound and kids, don't get too comfy just yet.