Don't 'ya just hate it when people act like that!!
I was thinking about what I'd have said and this is what I came up with:
"At lease mine are in a stroller. Who let you out without a leash?"
I have a stroller and I've used it a couple of times. It makes it easier to take both mine to the vet at the same time and keeps them safe. Makes perfect sense to me.
__________________ Kim , Rebel ,and baby Dixie 
RIP my sweet Lucy |