My 12 year old tortoiseshell used to go outside but has not done so for 6 months due to being scared of our neighbour's cat. She is using the litter tray proficiently but the stench of her poos has worsened and they now absolutely stink. She has a sachet of wet cat food a day as well as some dry food. Nothing has changed in her diet. We can't understand why the smell is so strong. Does anyone have any ideas as to what could be causing the change in smell?