He is so adorable!!
He doesn't look to bad if you were going into winter, but since you are in spring- Australia- I would be a little worried about it.
Keep the grazing muzzle on, and could you bring him into a dry-lot? Preferably not a stall, as in a dry-lot they can move around, but a stall they are cooped up.
Is he fed any grain? If so, take him off it and get him on a vitamin and mineral supplement for nutrient needs.
“Good things come to those who wait… greater things come to those who get off their ass and do anything to make it happen.” - Unknown