Totally agree with Tim, this is a very unusual presentation for constipation. The most common thing to see in animals with this condition are bloating, inappetance and cloacal prolapse not forelimb paresis. There are a multitude of conditions that may present like this and MBD would be high on the list especially given the husbandry conditions you listed.
As far as taking animals to the vet a little common sense is required. If you were sick (ie paralysed) would you wait a week to see the doctor?? The earlier animals are seen by a professional the greater the chance of diagnosis and resolution of the problem.