It is an acquired taste and the coarse texture of the kernel likely foreign to them. We all know chickens don't like change.
I grow a bit of extra corn so I do rub a cob off for them, once in awhile. However, I feed a high protein feed. Corn is only 9% protein and isn't a complete feed, of course, so I don't wish to dilute the complete feed too awful much.
If one fed a whole bunch of corn and a 16% type feed, it is pretty easy to dilute their protein level down to 12% and I don't wish to do this. Bugs are not in supply now around here as we have regular frosts and winter will be upon us soon. So finding protein through ranging is getting impossible almost.
Finally, the regular feed is corn based. It is likely our bagged, complete feed is already 70% corn. Adding even more corn and more corn isn't going to be a great dietary supplement, in my case.
So, a bit now and then? Yes, they eat it. Cracked corn is sometimes more palatable to them, but cracked corn is pricey, for what it is. My $.02