
Who told you to growl back ? The dog is warning you & then you warn the dog, I would like to know what that is supposed gain you, some people(not you)do have some very strange ideas
Something connected with the lead is obviously worrying him. You need to make it a rewarding exercise for him to have his lead put on & to want to go for a walk
Does he have a collar on all the time or does he object to having a collar
& lead put on(he has to wear a collar & tag of course when he goes out) ?
Or is it just the attachment of a lead to his collar that he objects to ?
I do all my heelwork training off lead at home & my dogs wear collars & tags 24/7, so putting a lead on means they are going out which they love to do so they are willing to have a lead attached
As this appears to be a fairly recent behaviour has anything happened to him when he has been having a lead put on or whilct wearing a lead.
Does he have any little lumps or bumps on his neck that might hurt whilst wearing the lead ?
What sort of collar does he wear ? could that be hurting ? There are so many different things that could be making him frightened of wearing the lead/collar & lead you need to think about what happened before he got upset about it