Retriever freezes when lead attached

Hi Tosca, thanks for your post.
I think the behavior your dog is expressing is predominantly fear. It may be that she has previously been abused in such a way that makes her head shy for example dragged on a prong collar or kicked etc while tied up, or it may be that having been kept confined all her life she has a fear of the big bad world because she saw none of it during her socialisation period as a puppy. It could even be a combination of the two reasons. Whatever the reason the solution is to desensitize her to all aspects associated with being on the lead and being out doors. This is done by slowly introducing new things in short non-threating doses while ignoring nervous behavior and rewarding all calm behavior. You don't say if she will wear a collar or not but if not try to get her used to both collar in lead in a non threatening way first. Bring them out into the room with her and put them gently on the floor, if she approaches to sniff or walks near them calmly then immediately but gently praise and /or treat. (If she will not approach them and is scared to walk anywhere near them even after a few trys, try putting a little food near them and praise every time she goes anywhere near them till she is comfortable). Once she is ok with this step advance to holding them in your hand and later holding them near her body again ignoring nervous behavior and rewarding calm behavior. Also try to desensitize her to touching her head in a similar manner. Once she is good with these try clipping a lead to her collar from her side so that your hand is going under her head and nothing is going over her head and neck so it is less threatening. Do not hold the lead initially but just keep praising her for calm behavior while it is attached.

Also desensitize her to going outside. Try feeding her on the door step and eventually try taking her out just on the lawn on her lead and feeding her there. Try doing all of these in several very short lessons a day. If she becomes to nervous always go back a step. Until she is fully comfortable on the leash in the yard and later the near by street it is best if you don't take her on walks because this may be just too much for her in the early stages and make cause her to get increasingly worse.

Also the most important thing to remember is that all the time you should be positive and try and have a bit of fun because these emotions will be passed on to her. Always encourage any playful and calm-non nervous behavior. If you catch on to thing she enjoys doing or playing with try and incorporate them into the training for example if she likes a certain ball try and play with it with her outside or even inside while the leash is on initially to distract her from worrying about the leash being attached.

I hope you find this useful and let me know how you get on, golden retrievers can be a real joy and you have done an excellent thing in rescuing them.