cockerel with a red featherless bum

hi hope someone can help
we have a young bantam cockerel ,his feathers look more like fur and around his bum he has lost his feathers and its a bald red patch  the 12 hens hes in with had been ok until today ,3 of them have feathers missing from there neck just white skin there now    could this be mites if so any ideas what to get them .big problem with cockerel would be picking him up as hes just starting to get used to us dont want to scare him by catching him to dust him in flea powder if its mite is there any spray i could get ?soz 4 rambling but chickens on next lottie are all covered in big bald patches and id rather sort mine out b4 they get thet bad
                                                                     thanks
                                                                                brenda

thanks aunt sally
weve had the hens for 5 months with no probs til we put cockerel in 2 months ago ,we do shed with jayes fluid ,is there a spray you could recommend for lice and mites ,also would we use that instead of jays fluid in shed or use both aswell as treating birds
                                                            thanks