How old is the pup? When I normally start to train for show on a puppy and this is me personally I don't even put a lead on until they are almost 6 months and then when I do I put it on and let them play with it, drag it around with supervision of course and go from there. Of course this is when I keep a pup from my own litter. Normally when I get a younger dog for show and I'm talking they are already over 8 months normally they are lead trained and I work with them to get use to me.
I believe the first months of their lives they need to be pups and get over the fear factor and that typically doesn't happen until they are around 5 to almost 6 months of age. I've never had any problems lead training with my methods and they normally go in the ring the first time with no hesitation
It's like they've been on the lead for years
Hope this helps.
Donna