IBD has very noticeable symptoms. Here is a link: http://www.reptilechannel.com/reptil...y-disease.aspx

My first thought is that it could be impaction. Repti-bark is very bad for a snake (especially a juvenile) if it is ingested. You might want to take him to a vet and get an x-ray. Also, I would recommend switching from repti-bark to something that can be passed if swallowed (like eco-earth) or just use paper towels.

Good luck and keep us informed.