Dictionary

off one's feed en · ADP

(of an animal) Not eating normally.
- "My dairy farmers tell me that because of the heat the cows are just off their feed." 1998 August 12, Rick Lyman, “Drought in Texas and Oklahoma Stunting Crops and Economies”, in New York Times, retrieved 02 Aug 2012:
- "Nothing serious," the veterinarian added. "He was just off his feed a trifle." 1915, Jack London, chapter 12, in The Little Lady of the Big House:
(idiomatic, of a person) Rather unwell, especially with a reduced or altered appetite; somewhat disoriented or disconcerted.
- The heavyweight champion of the world was off his feed. . . . Rocky, ordinarily a first-rate trencherman, was pushing away from the breakfast table after downing only two eggs and a pair of lamb chops. 1954 June 28, “Sport: Bumbling Champ”, in Time:
- I asked some questions about Jack Benton, and one of the men told me that he was off his feed, and hardly ate anything, and swallowed all the coffee he could lay his hands on, and had used up all his own tobacco and had begun on what his brother had left. 1903, F. Marion Crawford, Man Overboard!:
- ‘Something is the matter with Psmith. He is off his feed. He should try Blenkinsop's Balm for the Bilious.’ 1915, P. G. Wodehouse, chapter 24, in Psmith, Journalist:
- “He wos took wery bad one arternoon, arter having been off his feed, and wery shaky on his legs for some veeks.” 1841, Charles Dickens, chapter 4, in Master Humphrey's Clock:

under the weather (rather unwell) · inappetent (in veterinary medicine, of an animal) · out of sorts (rather unwell)