What size does the Ovarian follicle should be? how many does a women release each month? ?

Yes, there is definitely a chance. I had four follicles all less than 21 and I got pregnant with twins. In a normal cycle without medications, a women will produce one follicle. Rarely a woman will produce two which results in twin gestation. Most people say follicles can be from 18-25 but mature follicles can be obtained at smaller sizes.