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.Please Please do not mix the Orps with the Marans. Marans have so many problems on their own without more added to the mix. There are some very nice Whites out there already,I have been hatching from mine like crazy this Spring with very good results.