She's 5 years, it's very deep moaning sometimes. She gets fed at regular times.

Biscuits in the morning, then goes out till about 1pm.
Has her main meal at 1pm.
Has a sleep for a couple of hours, then has some more biscuits.
Goes back out at 6 or 7pm in the evening, then comes in about 11pm, then has her evening meal.

Never leave her out all night. We have our own wistle for her she always responds.