I have recently taken on a lovely spaniel cross who is nearly perfect in every way but she will freeze in certain situations - when we leave the house, when she has to cross a wide road (she is fine with narrow streets) when we return home from a walk (she is reluctant to go back in), occasionally when we are on the walk.
I have tried the obvious things - coaxing with treats and rewarding with bright chat when she does move eventually after making her point.
Twice she has stopped mid-road and I have had to pick her up (fortunately she is not a huge dog) and keep her safe. This has only come on lately - first few walks we did she was fine.
I have varied the walks, tried quiet traffic free times early in the morning but it is very wearing not knowing when she will refuse to move. I walk her on a loose lead to enable her to do spanielly sniff things.
She is a lovely dog and I don't understand it as I have never had this problem with any of my previous dogs