My bearded dragon is about 3-4 months old,i had him on a birdseed substrate for about a month now?

i would call a vet that specializes in exotic animals and see why this is occuring cause it might have been a thing where the bearded dragon couldn't handle the birdseed substrate he was on its important mabe to not give any more of that diet he may be constipated and can't go you could also call a pet shop and see what they say call one that has the bearded dragon at their store they might be able to help it might be something totally different then the diet you have him on