Jim, it looks like you have a good start on a fall garden. I hope you will continue to add plantings of turnips, probably up until Nov. 1. Those turnips will need to be thinned just as soon as they get big enough to make "salad." Those you leave after thinning will then have room to make roots and spread out and make lots of greens.
Even though you put down chicken manure, you will still need to add a little nitrogen. The nitrogen in the manure isn't available to the plant all at once. Don't get me wrong; chicken manure is very, very good fertilizer, and will continue to provide some N throughout the winter.
You might also want to thin some of the collard plants as they get about six to eight inches tall, and transplant those you pull up. Set them about 12 inches apart and they will make some big collards in a hurry.