Try a Harness and not a collar.. I'm sure if i put a collar on my dog he'd
probably slip right outta it too... my Min Pin is almost two years old now
and for the first year..everytime outside.. whether it was just playing in
the yard or taking him for walks .. he always had on his harness.. .. now a
year later.. i can let him run free in my non fenced in backyard.. he
quickly learned his boundries.. now of course when i take him for a walk..
harness and leash are back on... but def try a harness .. they cant' slip
outta them nearly as easy...