I think your Japanese may be your only problem, and maybe the hybrids depending on what mix they are. Can Cochins fly or are they more like Silkies? I'm not very familiar with the breed.
X2 It really varies from breed to breed, and your personal preferences. Jumping capabilities have to be determined by weight more than anything. Also the types of birds. The only breed that are in my fully inclosed run is our Silkies. (I worry about them more than the rest). The rest free range...