A macaws beak is extremely hard, unless it suffers from illness or injury, it should be fine with dry food. If you pet likes it moist, will, can only eat it moist, I think moistening it is okay. Adding a little water makes it easy to eat, but over time, it also promotes the growth of bacteria which can harm your pet. Learn what your pet's eating habits are and as soon as it finishes a regular feeding, I would remove the moist food and wash out the dish. You can always use more than one dish, and have a dry dish always available with a moist mix only at feeding time.