I think they know...they certainly know when we are upset with them,
so I think they know how much we love them, too.
Boo is a rescue and there's no doubt he understands and is appreciative of the love and care he has now. He shows it every day in his efforts to do what we ask. He's always up for a cuddle or rough housing.
Gracie Ruth & Yogi came from an amazing breeder who showers her gang with love and, of course, they get smothered with love from us. So although they may not know what it's like to not experience love, like Boo has, I'm sure they know they are loved and cared for. They can be very independent at times, but when they don't feel good or are scared they quickly seek out me or DH for comfort and reassurance. One of the best feelings is to be at the Dog Park and see them suddenly start search for me. The look on their face when they 'find' me is priceless.
