That old sense of acorn as promordial food, preceding agriculture or even hunting, just lying around (Gilbert White--"Man in his true state of nature, seems to be subsisted by spontaneous vegetation") reinforced by the pigs legendary fondness, floats all across these OED examples--especially liked "the Hogges bothe male and female haue lykynge to ete Akernes."

2. a. The fruit or seed of the oak-tree; an oval nut growing in a shallow woody cup or cupule.

c1000 Ælfric Gloss. in Wright Voc. 33 & 80 Glans, æcern. Ibid. 284 Glandix, æceren. c1350 Will. Palerne 1811 Hawes, hepus & hakernes, & þe hasel-notes. 1387 Trevisa Higden (Rolls. Ser.) I. 195 (The Athenians) tauŠte+ete acharns [Caxton acornes]. Ibid. II. 345 Toforehonde þey lyued by acres (= cum ante glandibus sustentarentur). 1388 Inv. of Goods of Sir S. Burley in Prom. Parv. 6 Deux pairs des pater nosters de aumbre blanc, l'un countrefait de Atchernes, l'autre rounde. 1398 Trevisa Barth. De P.R. (1495) ix. xix. 357 Nouembre is paynted as a chorle betyng okes and fedynge his swyne with maste and hockornes. Ibid. xvii. cxxxiv. 690 The hoke beeryth fruyte whyche hyghte Ackerne. Ibid. xviii. lxxxvii. 837 Hogges bothe male and female haue lykynge to ete Akernes. c1440 Prom. Parv. 361 Ocorn or acorn [1499 occarne, or akorne] frute of an oke. Ibid. 6 Accorne or archarde, frute of the oke. a1500 Nominale in Wright Voc. 228 Hec glans a nacorun. 1500 Ortus Voc. Accharne, okecorne. 1509 Fisher Wks. 234 (1876) He coude not haue his fyll of pesen and oke cornes. 1523 Fitzherbert Surv. xxix. 51 Ye must gather many akehornes. 1547 Salesbury Dict. Eng. & Welsh, Mesen An oke corne. 1549 Compl. Scotl. xvii. 144 (1872) Acquorns, vyild berreis, green frutis, rutis & eirbis. 1551 Turner Herbal. iii. 109 (1568) The oke whose fruite we call an Acorn, or an Eykorn, that is the corn or fruit of an Eyke. 1552 Huloet, Woode bearynge maste or okehornes, Glandaria sylua. 1565 Jewel Repl. to M. Harding 302 (1611) They fed of Akecornes, and dranke water. 1570 R. Ascham Scholem. 145 (1870) To eate ackornes with swyne, when we may freely eate wheate bread emonges men. 1572 J. Bossewell Armorie ii. 74b, To assuage theire hongre at euen with the Akecornes of Okes. 1580 Tusser Husbandry 28 For feare of a mischiefe keep acorns from kine. 1580 North Plutarch (1595) 236 The Arcadians+were in olde time called eaters of akornes. 1586 B[eard] La Primaudaye's Fr. Acad. II. 117 (1594) The hogge, who with his snowte alwayes towardes the earth, feedeth upon the akornes that are underneath the Oakes. 1594 Plat Jewell-house iii. 13 You may feed Turkies with brused acrons. 1597 Bacon Ess. 256 (1862) Satis quercus, Acornes were good till bread was found, etc. 1611 Heywood Gold. Age i. i. 11 He hath taught his people-to skorne Akehornes with their heeles. 1611 Cotgr., Couppelettes de gland, Akorne cups. 1613 W. Browne Brit. Past. II. ii. iii. (1772) 96 Green boughs of trees with fat'ning acrones lade. 1627 May Lucan vi. (1631) 481 That famed Oake fruitfull in Akehornes. 1632 Sanderson 12 Serm. 471 Vnder the Oakes we grouze vp the Akecorns. 1640 Brome Sparagus Gard. 113 Leekes, and Akornes here Are food for Critickes. 1649 Lovelace Grasshopper 34 Thou dost retire To thy Carv'd Acron-bed to lye. 1651 Hobbes Leviathan iv. xlvi. 368 They fed on Akorns, and drank Water. 1664 Evelyn Sylva 15 (1679) Any Oak, provided it were a bearing Tree, and had Acorns upon it. 1674 Grew Anat. Plants i. i. (1682) 3 Oak-Kernels, which we call Acorns. Ibid. iv. ii. iv. 186 An Akern, is the Nut of an Oak. a1682 Sir T. Browne Tracts 27 Some oaks do grow and bear acrons under the sea. 1712 tr. Pomet's Hist. Drugs I. 81 The Acorn of the Cork is astringent. c1821 Keats Fancy 248 Acorns ripe down-pattering While the autumn breezes spring. 1859 Coleman Woodl. Heaths & Hedges 7 The young trees usually first produce acorns when about fifteen to eighteen years old.