Have you checked the feathers around the girls vents? I haven't had a problem with my Rhodebars having feathers interfering with mating. But I have to keep my Orpingtons trimmed around their vents.
Did you check your fertility? It could be as simple as switching the roosters to the other pen. The first thing they will do is run around & try to cover all the hens. I serve eggs every Sat morning to my family :) They get a good breakfast & I check for fertile eggs. It is strange for 2 incys...
This is Snickers. She is about 3 weeks old. She is a Rhodebar pullet & much darker than my original Rhodebars. I too like their personality & they lay circles of eggs around my Cream Legbars. Who like to quit laying every time it gets too cold or hot.