@bluejean55girl: As far as I remember someone has done a study on natural selection in chicken flocks, (don't ask me who did it, I suspect a swiss uni, they did a lot on livestock in the 80's): If I remember correctly hens were attracted to roosters with deep red combs and wattles. Avoiding roosters who were artificial made paler or who's combs were made to looked like picked on or looked like they had a mite infection. Same thing with feathers. Roosters with full plumage and shining feathers were choosen over roosters that were dusted with dark powder or had raged or partly pluck plumage. They draw the conclusion that hens go first for healthy looking roosters and than choose from them the rooster who performed high in "rooster duties" like finding food, dancing, looking for save nesting places. And they said that the rooster duties, too, were a pretty good indicator for health. The argument was that a rooster with parasites or other illnesses just could not afort to give as much food away to the hens, could not dance or look for nesting places as perseveringly as a all healthy rooster.
I think this is very true for hens and roosters who do not know each other, but my girls seem to take a secound look and choose an older, more experienced roosters over the best looking youngster. My youngest rooster looks perfect form me, while my olderst rooster has an x-beak, a crooked comb and well, his feahters are fine but he is def. not breeding stock. My youngest can dance and call the hens for food, dropping big worms in front of them and still they run from him and crying bloody murder when he comes near while squating for my old boy everytime stands behind them. My older rooster get showered with all the little signs of affection by the girls while my youngest can be happy if some of the lower ranking girls is okay to sit beside him at night.
Sometimes I pity the youngest, but I know some day he will convice some hens to follow him around. Til than he will spend many lonley hours food dropping and talking to himself and getting beaten up by one of the other boys for being too "nice" to one of the girls. Being a young rooster is not easy.