I think the hairs for hackling have a wide spot at withers and base of tail, but down the spine it's just not as wide. Or maybe it's different for different breeds? Asha's "mild" alert starts at the withers and at the tail, but if the hair down the spine also comes up, it's just like your photo, thiner down the center of the spine. And yes, full tilt at the ready.Our original trainer told us that if the hackles are in a thin line it's fear and if they are wide it means they mean business.
The other day I was walk our road out here and I saw her hackles coming up on the withers and her trot started getting stiff, then the hackles came up on her rump, so I leashed her up. Around the bend there was another lady walking her dogs toward me. We said hello and talked a bit and Asha was already chill about it, but when she knows something is different, but doesn't know who or what it is, her body language shows it all.


It's never ending.