I don't know exactly how thick Nee's neck is. I DO know that this summer, when he had outgrown his baby collars, I put his 21" slip on him all the time (I'm a horrible mommy I know). On August 17th, his first birthday I got him a rolled leather collar, the biggest one they had, I didn't look at the size. But we couldn't put it on right away because the slip wouldn't fit over his fat head, so we had to cut it off. He's outside right now, when he comes in I'll measure him.
Where do you measure? Behind the skull? Or right over the chest?
Stella, Nee isn't big, he's just fat!