Hi all as you remember I have Smokey 12 1/2 yr old dwarf mix and Paulie a 2 or 3 yr ld mini lop.. I have never ever had this probelm with Smokey.. but I had Paulie and Smokey outside today and I noticed a huge amount of hard poo caked to Paulies butt. So I took him inside and soaking him in the sink and got it all off. What causes this? now his nice white fur is all stained by his bum and not to mention GROSS