I understand that most fish spawn in the spring to ensure some of the hatch reaches a big enough size to make it through winter. My question is when do females start to develop eggs? After a heavy gorging in fall and assuming periodic feeding under the ice, it must take an incredible amount of her reserves to gestate eggs. I know they also will gorge before the spawn but this is after the development of the eggs I am guessing. So, I guess my question is basically when do female bass start to develop eggs?

The exact length of time in months I can't give you but bass start developing eggs not long after they lay this years eggs. The exact time of the spawn corresponds with moon phase, amount of sunlight, water temperature, and gestation period. Each individual bass spawns during its own time frame according when the parameters listed above are met.

Bass eggs are fully developed in late fall early winter.  This occurs for several reasons.  The eggs are develped while resources and metabolism are still fairly high, it would take too much energy to develop them in winter/early spring just prior to the spawn.  Also, they are fully developed during this time period such that zero energy is expended just before the spawn and so that when conditions are right they can immediately spawn and not have to wait for eggs to develop.  Hope that makes sense.

IMO, another reason we get a great bite in the fall is because the bass need that extra energy for egg development (as well as put on extra fat for the cold winter period).