Okay, you gave a little background but what are your goals? Do you want to have a cow /calf operation or do you want to only raise steers or feeders and not have to feed through the winter? You asked for some advice, but without knowing what you think you want, it is hard to advise.
You said that you have AI'd the heifers, so they must have some pretty decent breeding. Do you want to continue the bloodlines?
Is the 50 acre pasture available for sure every year? I am assuming that you are from Ky so the growing season is fairly long so you will have a long grazing season if there is rain to keep up the pastures. If the 6 acres is available then yes I'd fence it. Only you can judge the pros and cons of making the hay or buying it. If that is the only place you make hay on then you have alot of money tied up in equipment. I'd fence the hayfield if it is yours and then you have the option.
Right now feeders are bringing decent money, but remember that the larger they get the less per pound. They have been alot higher, but could also drop like they did in the past 2 years but most of us sure hope they don't. Good weight gain on steers is in the range of 2-3 lbs per day so hope for 60-90 lbs per month; for 9 months you can look for 6-800 lbs if conditions are good. IF IF IF.... there always variables and some people can get more gain, sickness can throw you off and there is possible death loss to think of.
We are cow/calf, keep some of the calves for a little while and sell according to the markets. Most all our land is rented. We raise our best heifers up for replacements, and buy some cows too, all according to what we can find and what pastures are available.
I would sell the open cow. If she has some age then there is no reason to keep her. she is not going to make you any money. Selling her is better than burying her.
