I think the answer here will be one that will differ from breeder to breeder. Myself, I practice breeding 2 days, once in the AM, once in the PM. I will also add that we had fertility test done on her during her 1st and 2nd heat to determine when she was most fertile.
Just remember, your goal should be for the healthiest litter possible, which often times is not the largest litter possible. I am a firm advocate of health over quanity.
