Feeding only chicken is not complete enough. Raw beef is the main meat of raw feeders. Constipation can be from too much bone and organs should not be fed every day, maybe only once or twice a week. Premade raw is the easiest to feed as it is a complete diet.
The butt rubbing could be irritation from having diarrhea which is caused by feeding only chicken and possibly too much bone and organs. There is a raw thread that explains in great detail how/what to feed when it comes to raw. Make sure to read through it as it gives a lot of valuable info.