Refuses to walk

[GIDEON SMITH]

When on walks my dog decides to sit down and won’t move. 
 

I use a slip leash but even the tug on that leash doesn’t get him up etc. and I have no idea what to do or how to fix this. 
He doesn’t do it all the time but when he does even a treat lure doesn’t get him up. 

[Adrienne Farricelli]

Hi there,

Is this behavior totally new? Was he doing fine on walks before?

Have you noticed any correlation with something happening in his surroundings when this happens? (Noises, presence of other dogs, people?)

How long are the walks?