Here are a few tips for judging California Bighorns, I may be wrong but I believe the species are the same in Orgeon.
This link takes you to a YouTube Oregon Sheep hunt video:
YouTube -Bighorn Sheep in Oregon
Mass over length: Because a ram has four circumference measurements versus one length measurement per horn, good mass is critical.
Blocky bodies, thick necks: As with most other big game animals, trophy rams are most often mature creatures that are potbellied, swaybacked and thick-necked.
Promising curls: Look for full curls that come down below the bottom of the jaw and sweep back up beyond the sheep's nose or even higher.
Horn length: Most record book thinhorns will typically sport horns measuring 35 to 40 inches in length. World-class rams sometimes measure in the mid-40s or better; in fact, the world record Stone sheep (the Chadwick ram) sports horns measuring more than 50 inches on both sides! Bighorn trophies will often tape out at 35 to 40 inches, with a few mega rams approaching 45 inches in horn length.
Base circumferences: If thinhorns are king when it comes to horn length, bighorns are tops for mass. Look for base measurements of 14 to 17 inches on bighorn sheep. For thinhorns, top end rams will have base measurements from 13 to just under 15 inches.
Unbroomed and unbroken tips: For better symmetry, and thus, less deductions, look for rams that sport clean tips that haven't been broken or worn down.
Hope this helps.
