Brady is a great little guy - responds well to training, etc. He has his moments but overall he's doing well. We use the (slip lead) leash about 40 percent of the time, and moving to more as he expands his horizons. There are times (even at the beginning of a walk) that he just lays down, refuses to move, like a toddler who says "I WON'T". I wait, and eventually he does get up. We have tried some treats when he DOES get up, but I don't want him associating lying down and refusing to move with a treat. He might just be bored with the yard (despite balls, fetch games, and rocks to climb on) because he doesn't do this when we are someplace new. We do start obedience training this week and it's one of the questions I'll ask. Any advice welcome....
A little harness would be much better and safer for your puppy than a slip lead, particularly when he gets to go new places and might get excited and jump around a bit - leads that tighten round the neck aren't great things to train with, really. Even collars aren't great, harnesses are much safer. There is always a reason a puppy won't move on a lead - he is not just being awkward and saying 'I won't'. Thankfully, dogs are more civilised than human child in this regard. Sometimes, if in a new place, they are just looking around, taking in a new environment. It can be because the puppy just does not know what's expected, and is confused, or is finding walking on a lead an unpleasant experience - leads are very restrictive for puppies, they stop them going where they want (obviously) and that alone can be a bit frustrating. Sometimes they can find the walking equipment used strange and uncomfortable, and (not saying you are doing this) any jerking or pulling on behalf of the human can be upsetting for a small pup. It isn't quite clear where he is doing this - in your garden (yard) or at the start of a walk or on a walk? Anyway, the best thing to do is train him to walk alongside you without a lead - you can do this in your garden at first. There are instructions on the main site about how to do this with a clicker. Once he can walk alongside you in the garden (for plenty of food rewards) then you can introduce a lead. If you are out and about on a walk and he stops, while you are still training, by all means encourage him along with treats. All you are doing is luring him back into the position you want him to be in, walking alongside you. This won't make him more likely to stop - unless you give him the treat when he is stopped, or don't give him enough treats for walking nicely without stopping, or you don't fade out the need to use a treat by training (as above).
Interesting idea about a harness..will check it out. Thank you Amazing that he really does go 'on strike'. He loves new places and new things. He'll do it in the garden. We thought he might be tired. When he knows I have the treat bag (and he gets them periodically on the walk) then he does just fine. We have been working a lot off leash and he does reasonably well. We will take him places with many distractions (and other dogs, and leash laws) so he will need to be on a lead at times.
A harness is certainly worth trying. My black lab used to sit down and not budge when she first started going out for walks and she wasn't particularly encouraged by treats although she's usually very food orientated. I bought a harness and found it much easier to encourage her to walk. Perhaps she didn't like having the lead attached to her collar, although she still wears a collar anyway.
You might be interested in this article by Emily Larlham: http://dogmantics.com/is-it-harmful-to-attach-a-leash-to-your-dogs-neck-2/ Either he doesn't understand what you want, or isn't sufficiently motivated to do what you want (or is scared, or uncomfortable). I suppose that might be justifiably called 'going on strike'. The solution is to pay him better (or stop him being scared, or uncomfortable). There are some useful articles on the main site that will help you overcome the problem of training in a way that means your puppy has to see the food or treat bag first - it's all about using food properly in training.
My boy never saw a lead until he was three months and we started taking him out of the yard and also in some public places. He was more than happy to follow as most naturally do anyway at a young age. He also sat and refused to budge even and at 4.5 months he still sometimes does. There will always be a good reason to him why they do this. Perhaps a strange scent across the path, tired from growing so fast and several other reasons. It's important not to pull or force them until they are ready to move. Be confident so they feel protected and they will trust you more and it will get better over time. They all do it. Puppies aren't meant for long walks anyway.