Mottled cochins are very beautiful birds, if you want to see some exhibition type Mottleds go to cochinsrule.com and look at the cochin photo page. You may also check out the members page and find breeders of these birds who are more than willing to share and get more people interested in cochins.
As an answer to the post about Murray McMurray cochins and them not feathering on the back, I would reason to guess that both of these chicks are males, right? The reason cochins, both bantam and large, do not feather sometimes on the back and abdomen is because the males lack the rapid feathering gene (most times the females do as well) found in most production types of chickens (New Hamps, Barred Rocks, Delawares). These birds will eventually feather but I would recommend if you want birds to be fully feathered for shows and fairs, especially since they are earlier in the summer and fall, order the chicks as soon as they are available in January or February. Ordering them that early gives them ample time to feather and reach maturity, they will be in better feather condition and will stand a better chance of placing well due to maturity.
I would also state that for county fairs hatchery birds will probably do OK but if you are planning on a State Fair or an ABA/APA sanctioned show you need to seek an established breeder of exhibition quality birds. There are breeders of all varieties of bantam and large cochins to be found at the web site I listed earlier.
Just remember to be patient where cochins are concerned, they mature slowly and I normally don't cull, except for serious defects, until they are over a year old. Culling any earlier would lead to possibly removing a good bird from the flock.
Bo