My son arrived at FCI Terre Haute and has been placed in restrictive housing why and for how long is that normal for them to be placed in. 

The federal intake usually starts with a short bid in the SHU. The reasons they use vary from "missing paperwork", "bed shortage", "custody level adjustment" to name a few. I was designated to a camp and had to sit in the SHU for two weeks until they decided it was time for me to report to the camp. It was not fun and I was very happy when they released me into the gen pop.