That makes sense, but the pollsters were delivering weekly polls in IOWA, regularly. The best I can come up with is the volatility right now, with TRUMP challenging that Cruz lead of a week ago, or so, and the fact that it is now 7 days out, or what ever it is. Thanks entropy.
I am sure a few more polls will pop-up before February 1st. may be they are waiting to see if voters are solidifying their support to a particular candidate.