They are both nearly seven years old and together eat about 220 pounds of bamboo a day. The zoo relies on bamboo donated from private lands to feed Lun Lun and Yang Yang. The zoo uses their own team to harvest the bamboo, but I think it would be more interesting if they simply took the pandas out to graze at the site.
Of notable interest is that the zoo has a webcam of the pandas, available from 10am to 5pm (EST) Tuesday through Friday. Of course you can guess what they spend most of the day doing.