Bad genes?

[BTEQUINE]

Hello all, I purchased chicks from McMurray hatchery they were delivered (to Fairbanks AK) perfectly healthy and all started growing well. At about 4-5 weeks I noticed the partridge cochins were not growing feathers. I have whites, blues and black Cochins the same age, fully feathered now at 9 weeks. Of the 5 partridge Cochins 1 has feathered out. The other 4 are small, and mostly naked. All fed the same, no picking. I can only assume bad genetics? Any ideas?

 

[chickenlittle21]

Can I see pictures?

 

[BTEQUINE]

 

[BTEQUINE]

 

[chickenlittle21]

They seem to be developing fine

 

[BTEQUINE]

So they partridge Cochins are supposed to develop late? Every bird in those pictures were hatched the same day. And received the same care