Don't walk your dog with the leash attached to the collar

Last night, I couldn't sleep and stayed up late watching training videos from Kikopup.  I found a blog post she made earlier in the summer about how walking dogs with the leash attached to the collar is bad for their health.  Not only are there potential neck injuries if your dog pulls, but it also affects their ears, eyes and is connected to hypothyroidism, among other issues.

If your dog is perfectly trained and never pulls?  That's awesome but there's always the chance something might happen one day where you need to pull your dog aside for safety reasons.  Would you rather have the leash be attached to a harness or the collar?  That's enough reason for me to not walk my dog with the leash attached to the collar!