bare butts and bumpy eggs

[woolychicken]

HELP!!!!!

I HAVE 18 LAYING HENS AND HAVE BEEN SEEING BARE BUTTS ON 7 OF MY HENS (MOSTLY MY 3 WYANDOTTES, AND 2 BUFFS AND 2 RED COMENTS)AND HAVE FOUND AN EGG WITH BUMPS ON IT? WHAT UP!! I THOUGHT IT WAS LACK OF CALCUIM SO IN THE LAST 2 MONTHS I HAVE GIVEN THE FLOCK ONCE A WEEK YOUGURT.
PLUS THEY HAVE OYSTER SHELLS ALWAYS AVIABLE,PLUS OILED SUNFLOWER SEEDS,WENT TO TURKEY GROWER FEED THOUGHT LACK OF PROTIEN,HAVE LET THEN RUN FREE ON OUR 2 1/2 ACERS 4 OUT OF 7 DAYS WHEN I CAN BE HOME. THEY GET OUT SIDE COOP BY 9:00 AM AND THE COOP SIZE IS 18 X 8 , CHICKEN YARD IS 30 X 35 . THEY GET STRATCH IN THE EVENINGS, WHAT SHOULD I DO NEXT? I HAVE BOUGHT ROOSTER BOOSTER NO PICK. BUT HOW DO I FIND OUT WHO IS PICKING?
I ALSO HAD ONE HEN THIS WEEK LOOKED EGG BOUND SO I DID THE WARM WATER BATH WRAP HER IN A TOWEL AND SAT HER ON A HEATING PAD FOR 1/2 HOUR THEN PUT HER IN A DOG PEN IN THE COOP WHEN I WENT IN I FOUND THE REMAINS OF THE SOFT EGG SHELL STRANGE

I DO NOT KNOW WHAT TO DO NEXT? MY ROOSTER IS A BIG GUY SHOULD I SEPERATE HIM FROM THE FLOCK FOR A WHILE . MY HENS LOOK RAGGED TO ME . WILL IT MAKE HIM MEAN? HES SO NICE. WILL HE GET DEPRESSED ? WOW WHAT CAN I DO !!

PLEASE ADVISE

WOOLY