What are Aussie ears supposed to look like?
The breed standards describe a moderate sized, triangular ear with a slightly rounded tip that sits high on the head. The ears may break forward or to the side (“rose” ear) when at attention.
The ASCA standard specifies that the tip of the ear should reach to the inner corner of the nearest eye. The AKC standard, on which most if not all standards in other countries are based, does not specify a length though presumably “moderate size” would preclude long or tiny ears.
The ASCA standard also specifies that the ear shall break (bend) between ¼ and ½ way from the base to the tip. The AKC standard does not specify where the ear shall break, so presumably either lower or higher breaks would be acceptable, so long as there does break.
Both standards declare prick ears and hanging (low set, pendulous) ears to be severe faults.
In practice, show breeders have a marked preference for lower- and forward-breaking earsets and that look has become almost ubiquitous in the show ring. Working and performance breeders aren’t as concerned about what the ear looks like as the trait is cosmetic. You will occasionally see prick ears in working or performance dogs but pendulous ears are extremely rare, probably because the look is so atypical of an Aussie that there has been significant selection away from it.
What are “rose ears”?
This is a type of earset where the ear flap is dropped but has a fold that makes it break to the side. This type of ear is seen in many sighthound breeds and some traditionally cropped breeds may have rose ears if the ear is left natural. They are seen fairly frequently in working and performance Aussies. They occur in showline dogs but are not preferred by most exhibitors and may be subject to alteration. It should be pointed out that rose ears are acceptable per both the ASCA and AKC breed standards.
How soon can I tell what kind of earset a puppy will have?
You will have a fair idea of what the adult earset will be by the time a puppy is a couple months old. Drastic changes after six months are unusual.