My husband and I are looking into adopting a dog. We have grown up in families where dogs play a large part, so we are used to having dogs around. He's used to German Shepherds, whilst I'm used to collies. We've gone through a couple of animal rescue centres and a possible dog has come up, a German Shepherd cross Collie. The dog is probably a stray so the staff have virtually no idea of it's past. I have heard that this particular cross is not a good one, but I'm struggling to find out more. All I've been told that you can get an aggressive hyper active dog. Can anyone help?