Yeah I know our Jess would never accept another adult dog but she has accepted pups before so I know she'll be able to accept another. She'd have to be closely watched though because I reckon she'd do some bullying to make sure the new pup knew where it stood. Our Mist used to be the one to do it and Jess didn't have to because the pups always made a beeline for Mist and ignored our Jess who was happy to be left alone but Mist never hurt a pup and used to get quite motherly and protective of them after the initial bullying phase. Still, I would never want to leave them unsupervised until I knew they were used to each other.