We practice 'trade' with Lucy. She is famous for getting some crap off the floor that she shouldn't have, then running, then getting a little snarly if you try to get it from her.
We've learned to just offer her a small treat - she will immediately stop running, drop what she has in her mouth; and come into the kitchen. The forbidden treat is immediately forgotten.
With two dogs, we simply do not leave chews, etc out on the floor - because both dogs will try to 'guard' their good chews. Those are given only in their crate. I know you have a new puppy - could this have triggered a little jealousy and/or guarding behavior in her?
On a side note, I notice my Lucy has a new game. She will not eat her food (she eats in her crate ~ door open; and Ringo eats in the kitchen) until Ringo is finished eating. Then she will RUN to her crate and start eating before he can get to it.
It's like a nasty little game she plays!
__________________  Mommy to Lucy, Ringo, and Matthew |