[cypher]

It does sound as though he’s unwell, it is possible he could have become constipated, if he doesn’t improve very soon I would get him checked out by your vet just to be sure what’s going on.
A pellet diet isn’t really suitable for a ham as they need plenty of variety in their diet, food should be enrichment as well as just basic nutrition.
Does he have fresh veg at all? Veg need to be introduced slowly but once they’re used to it having some daily is really good for them.
Is he drinking ok, water bottle working properly? Keep a check on that too.