When did you plant them? I planted mine the last week of July and they are still very small, the deer have been eating them as soon as they sprout which is really annoying me.
Mid -June. We had the same problem last year as you are having this year. We planted the other field in clover and it kept most of the deer over there until the turnips could get big.
Also, one of the other guys that hunts our property sprung for a soil test, lime and fertilizer for the whole field. That sure helped.