slowly over at least 2 weeks to a month move him on to excel pellets or another brand with at least 20% fiber in them. a shot a day is enough for a good weight rabbit, if yours cant clean his bum then he should only have half a shot til he can clean himself properly. also dont feed him any veg, just lots and lots of good quality hay not the cut up stuff u can buy in wilkos. and they like it fresh so pop a bit in twice a day. The Hay Experts - Natural Rabbit Supplies & Timothy Hay timothy hay again has more fiber than other hay types.

with the bum cleaning, you should be ok fly wise this time of year, but obviously this has got to be very uncomfortable, bathe him with cotton wool soaked in boiled but cooled water to get any bacteria out of the water, then make sure u dry the area off or they can get wet skin rashes.