This is the policy statement from the Hilton website:

Stays for up to two children aged 18 years and younger are complimentary when sharing a room with an adult. A second room for children aged 18 or younger is charged at 50% of the rate of the first room. Some hotels charge a supplement for families,or do not participate please check at time of booking. All children aged 10 years or younger are entitled to complimentary breakfast, lunch and dinner in at least one hotel operated restaurant, as designated by the hotel, when accompanied by paying adults currently staying in the hotel. Children are able to choose from the Children's menu or will be served children's portions; this also includes non-alcoholic beverages during the meal. These offers do not apply to room service.