Ruminants are usually allowed to graze between 10am and 6pm. This would have served them for the day. However, if feeds are served them in their ruminant housing, feeds should be made available ad libitum (i.e. As much as desired by the animals).
Feeds is supposed to be available for them at all times, Feeding time could be divided into two or three and the feeds being served them could also be rotated. i.e. the feeds served them should be of good quality and enough quantity.
See also: How to control Ruminants from destroying grasses where the graze