How do you tell if a pet is just unsure about a new harness or actually hates it?

That freeze is actually a pretty clear answer in my experience. My last dog did the exact same thing with a step-in harness. Just locked up like someone hit pause. No fighting, no trying to back out of it, just stiff legs and a look. That was her way of saying she hated it.

The harness that got a totally different reaction was the one she’d lean into after a few days. If your dog is avoiding eye contact, tucking her tail, or refusing to move even after you clip the leash, that’s not “getting used to it.” That’s discomfort. Mine never did come around to the step-in kind. I switched to a different style and the freezing stopped within a couple of walks.

So I’d say if she’s still doing it after a few tries, listen to that. Some dogs just hate the feeling of certain straps.

Standing still usually means unsure, not hate.

Freezing doesn’t tell you much on its own. My dog did that with a coat for a week and then acted normal once it got cold enough. If she’s still stiff after a few tries, that’s when I’d start paying attention.

A dog standing frozen like that is usually unsure, not hating it. Hating it looks more like backing away, struggling, or refusing to move at all once you start walking. Try a short session with treats and see if she’ll take a step or two. If she stays locked up every time, then I’d look at the fit.

Freezing like that usually reads as “this is weird” to me, not hate. One thing I’d pay attention to is whether she’ll still take food while it’s on. Mine wouldn’t at first but was fine after a couple days of putting it on for a minute at a time.

Freezing can also be a fit issue, not just unfamiliarity. My last dog stood like a statue in one harness and it turned out the strap was sitting right on his shoulder. Once I loosened that bit he moved around fine. Worth checking where the straps actually land before assuming it’s just newness.

Mine did the statue thing for a couple days but she’d still wag when I grabbed the leash, so I figured it was just weird-feeling. The tell for me was when she started doing it before I even clipped anything, like she knew. That’s when I stopped pushing it.