Where did u get that saddle? We've never heard of it.I just had this same exact problem! They were pecking her at the base of her tail. I cleaned it with soap/water and put a little antibacterial ointment on there. I used Blue Kote (I bought it at Tractor Supply) to cover the wound and that kept them from pecking her. 1. bc it is blue and 2. it is supposed to taste bad. Make sure you wear gloves as it stains.
Now, it has healed but still no feather regrowth so she is wearing a saddle now and it is working. Here is her new saddle. She is healing nicely.
Well that's the strange part. The first one that ended up dying because I caught it too late was dominkeers n the second 2 were Rhode island reds. First one of those died n I was able to save the second oneI bought the saddle at Louise's Country Closet. I think it was $3.50. It is pretty easy to get on too and she can still dust bathe with it on. It rained yesterday and it got wet so I had to put her in the dog carrier last night (didn't want her to get pecked in coop this morning before I let them out) so her saddle could dry. Someone else also suggested pinless peepers that you put on the mean ones that are pecking. I have never tried them though. Just a thought if it gets more serious. What is the breed of chicken that you have that is getting pecked? Just curious.