I have a female cockatiel that is dealing with smelly diarrhea due to egglaying. When I took some poo to the vet he said it’s was fine and it does not contain any parasites etc but that hormones could make it smelly as well. Not sure if that helps but you could take some poo to the vet to see if it’s free of parasites and otherwise it migh just be this toy that is triggering hormones?