Our Silkie roo used to jump on the Buff Orpingtons from the ramp to the nesting area. Their eggs were fertilized but not viable. I was never able to get the EE x silkie eggs to hatch, either. They'd fail about 1/3-2/3 of the way through incubation. The BO eggs wouldn't even start beyond blood vessels.
I had one several years ago. She hatched from a LF egg, but was in between a OEG and LF. Right now I have 5 cochin X BA babies and they all hatched no problem. Shouldn't be any issues. You may have to trim the girls vent feathers back since he is smaller and may have a harder time reaching them.
