Yes — and the cob is the best part
Chickens can eat sweetcorn in almost any form you would serve it: kernels off the cob, whole cobs, fresh, frozen or cooked. But if you want the full value of the treat, give them the cob. A hen eating loose kernels is finished in a minute; a hen working a whole cob — bracing it, tearing at the rows, chasing the pieces that break free — is occupied for the better part of an hour, and occupation is a genuine welfare good in a run.
Making a cob last
Wedge the cob upright in the earth, hang it from a string at beak height, or thread it on a holder fixed to the run mesh, and the flock has to work around and under it rather than bowling it into the muck. Cooked leftover cobs from the family table are fine once cooled, provided they are not slicked with butter and salt — rinse a buttery cob under the tap or keep it for the compost. Kernels cut from the cob suit bantams, growers and any hen at the bottom of the order who gets shouldered away from the main event; scatter her share away from the crowd.
Fresh, frozen, canned — the differences
Fresh and frozen sweetcorn need nothing doing to them beyond thawing frozen kernels to cool rather than icy. Canned sweetcorn is the one form to treat with suspicion: it is packed in salted water, and poultry have little tolerance for extra salt. If canned kernels are what you have, drain and rinse them thoroughly; better, let frozen be the standing standby and canned the rare exception. Dried corn — the hard field corn found in scratch mixes — is a different food again: much denser in energy, which makes it a useful winter evening scatter and an easy way to fatten a flock in summer.
Energy without protein: the honest account
Corn is a sugar-and-starch grain wearing a vegetable's clothes. It brings quick energy and very little protein, no meaningful calcium, and a flavour hens rate above almost everything, which is the whole problem: a flock allowed to fill up on sweetcorn will skip the balanced feed that builds its eggs. Treat corn the way you would treat cake in a child's diet — celebrated, occasional, and never the meal. A cob between several hens, or a modest handful of kernels each, is the scale that keeps corn a pleasure instead of a pattern.
Mouldy corn is a hard no
The one absolute in this article: corn that is mouldy, musty or has been stored damp never goes to the flock, in any form, ever. Field corn and sweetcorn alike can carry mould toxins that are acutely dangerous to birds, and hens are small enough that a modest amount of bad grain does real harm. Check scratch mixes and stored cobs with your nose; anything that smells off is binned, and the small saving is not worth a sick flock.
Sweetcorn lands in the run in bursts — a glut of cobs, a freezer bag split open — so put corn days on the record in KinsLe's Care Teams and the treat stays the event it should be, spaced between plainer days.