Big, wide head. The head is a tell tale sign of intelligence and vigor. The Rock, of any variety, looks like a Rock when you get the head right. They're composite birds and some of the "other" stuff shows up as small headed birds and Rock breeders need to guard against crow heads, flat top heads, flat back of heads, and one of the worst; skinny heads.
Clayton's number one cockerel has a very pleasing head. Striking really. The other cockerel he has shown lacks that nice head completely. That Clayton has a choice for his breeding program? Awesome.
Wide butts, fluffy butts. These are two different things. A nice bird is wide straight through, from shoulders through the back. I often demonstrate with youth that you have to notice several planes when evaluating. From above, from the profile and from the rear.
From the top, you should see no pinching, or narrowing from the shoulders all the way through the tail.
From the side, you should see no undue cushion fluff in front of the tail.
From the rear you should see a nice wide, angular tent formed, but you do NOT want to see a bulge of fluff down below, nor see that excess Orpington type fluff in profile view either.
Fluff around the thighs can also be seen from the side, from the top and from the rear. Again, 3 planes of examination. Often, this fluff is poor feathering, too soft. If you breed a patterned bird, such as a SPR or Barred, you'll often notice this fluffy, soft excessive feathering on the thighs also do not "take" the pattern well and is of a dull, off, muddied mess.
Yes, indeed. It's breeding season in Rock land. The happiest time of year.