I have a feed cooker that holds about half a bag of corn. Add water and plug it in and in 3 hours you have some beautiful feed. Personally I prefer cooking barley, as it doesn't get quite as sticky, but either corn or barley work good. The cattle almost go nuts over cooked feed. I would suggest you start the calves on dry feed and then slowly add the cooked grain. Mix it into the ration and I guarantee they will almost knock you over to get to it.
There used to be lots of these feed cookers around when I was a kid... which was a LONG time ago. I can remember lots of barns that had these things, which makes me think there must be some around yet. Like I said, ours would pass as being only a few years old. I would guess that our feed cooker is over 70 years old, but it looks almost new and works perfectly. I asked my dad where he got it from, and he said it was here before he bought the farm from my grandfather, which was in 1947. It has a baked enamel finish on the inside, which still shines when it is cleaned out. This is surrounded by oil that is heated by an element and once the feed is cooked, the oil will keep the feed very warm for at least 4 days.
Our farm was fortunate in that it received electricity earlier than many other places. I think electricity was brought into the farm in the mid 30s. Prior to that, my grandparents has their own power generator in the basement that produced enough power for the house. Our home was built in 1925, and it was wired for electricity and indoor plumbing when it was built.