All 3 ram lambs pictured at left look fully horned at ages of at least 4 -4.5 months.  At this age, horns should have at least 2-3 man’s fingers of width between them on the skull to allow for increase in thickness as the lamb grows.  All these lambs have at least 2 fingers of width.  The white lamb on the right has the most width between his horns at the forehead.   Horns most likely to clear sweep back, and out at about a 45 degree angle while at the same time they also arch up above the head and as the arch curves back down, the tips of each horn should be past the end of the ear.  Going by these guidelines, and experience, I estimate that the lamb on the right, Rugelach, has horns most likely to clear well at maturity (age 2-3 years).  The other two sets of horns might or might not clear–it will depend on how much and where they curve in as they grow and begin to spiral out.  Most will start to spiral out sometime during their 2nd year.