I think that different schools have different due dates for apps (late ~jan or past) but i know that they are also all on enrolling admission so you should apply asap to increase your chance. I unfortunately am taking the august mcat so will be applying late but I sure would apply now if i could
If you goto www.aacom.org, you'll find the deadlines of all osteopathic school deadlines. I recommend applying at your earliest convenience to maximize your chances.
Apply now, all DO schools are on rolling admissions and the earlier you apply the better your chances at an interview. As the application season progresses, there will be less slots, and thus they will be more competitive to get. Good luck!