They need the starch from the corn to get white fat. I usually recommend about 58 NEg, not quite as hot as fed cattle rations.

It's only worth feeding them if you can upgrade their quality.

Don't feed them more than 90 days - the pounds come on easy in the first 90 days, after that they can eat a lot but they don't gain a lot.

They need space, half again more bunk space and pen space then fed cattle.

Timing is important too, for example markets are usually better in February than in November.