I have a cock who chose 2 hens ... and tended 2 nests. Well - he kinda blew off most of his responsibility for the 1st one (which was also his 1st - ever) but every now and then - he was there. When he wasn't out courting the other hen, he did hang around nest #1 - I just think he didn't really know what he was 'sposed to do. They lost one of the 1st eggs to a bully bird so, fortunately, mom (who is an old hat at this stuff) only had 1 mouth to feed and didn't seem to notice the cock - 1 way or the other. I guess she taught him well, though, as he has tended to the 2nd nest (and babies) perfectly and still is - the babies are about 2 weeks old. So - it can be done ....