Another kitty conundrum- the reverse of a previous poster's dilemma!
My youngest dc (all 3 are rescue) has turned her nose up at the litter tray she used happily when confined indoors. She now prefers to poo in the yard. My other two cats can jump out of yard at will, but she has a deformed back leg which doesn't affect her speed of movement but makes her more wary of jumping and balancing.
They can also go out at the front on demand, but she hates being out at the front.
No medical issues I'm aware of. I think she was under 12 months when I adopted her last September. Has been starved, I think in the past- utter desperation for food but that has now lessened to normal cat imperiousness, which is fine.