86 is too low for ball pythons, though only by a degree--their lower temp is 87, so I wouldn't risk it. Cook them at 88/89F. Their eggs do have a rather narrow safe range.
How much does this snake weigh?
She maxes out my scale, which only goes to 1000g. She feels like she's around 1.5 lb to 2 lbs. Does she appear gravid to you?