This is a very important topic to which I have absolutely no knowledge... I am still pretty new to chickens. Could you elaborate a bit more on what the known problems with marans and orpingtons are so I can move forward intelligently. I chose an orp as an out cross for my golden cuckoo marans project because I wanted the lemon cuckoo color genes... and I really like the docile nature of the orps. My marans are all a good natured and show no signs of undesirable aggression but the orps are just soooo deliciously docile. For a small back yard breeder, this trait is pretty endearing. Right now , all my marans are 1/4 lemon cuckoo orp... next I was planning to only mix in pure gcm and bred back to type... I would like to know what to look for so I can eliminate potential problems... something more important to me than type. Your expertise on this would be greatly appreciated.