What's the physical difference between rough collie & sheltie? Collies; waist high. Sheltie; at most knee high

Collies are a much larger breed, and much more laid-back. They usually range from about 23-26", and have two coat varieties -- smooth and rough.

Shetland Sheepdogs ARE NOT miniature collies. I get this all the time at PetsMart when I take my sheltie. They are supposed to be between 13-16 inches, but I've got one that's on the smaller side (right under 12), and one that's about 16.5". They only have one coat variety, rough.

Coat colors are the same in both breeds. They can have a sable, tri-color, blue merle, bi-blue, bi-black, and others that are a result of mixing two.

I'm sure you could find more information on the differences on the AKC website

Their fur is not different colors.. I believe they can be the same color combinations. Shelties are much smaller. Collies are also a bit more of a "guarding" breed than a herder.. both are very intelligent and need mental stimulation and exercise to be happy. Shelties have a tendancy to be vocal ("yappy") if allowed to be, I'm not sure about collies. Collies are generally more calm than Shetlies, that can become skittiish without enough socialization.

Shelties have a "stop" , Collies don't.

A "stop" is easier to explain what it isn't. Collies have a straight line from forehead to nose. Shelties have like a bridge, like a forehead.

From the Shetland Sheepdog breed standard: "In profile the top line of skull should parallel the top line of muzzle, but on a higher plane due to the presence of a slight but definite stop."

We had a 50 lb. Sheltie. He was perfectly proportioned and could have been mistaken for a Collie except for the 'stop'. That, and we knew his parents, which were breed standard. It happens.