I'm at the end of my tether any advice would be great.
I've got 3 cats 2 girls 18 and 13 and a boy 7. The girls keep using my hallway as their litter tray! I even started locking them out of it. But even having the run of the kitchen utility garage and cat flap into big back garden as soon as I let them through to the rest of the house they mess. It's as if they hold on all day. There aren't any other cats around the garden area and they do play in the garden. I'm at a loss as to what to try. The boy is fine.