Good Run

T dog, Here are some of my thoughts on it and it might not be worth a hill of beans. lol I used to raise Russian hogs and could only get one litter a year out of them and these hogs were fed the best year round. It always seemed like they were coming into heat coinciding with the acorns dropping around Sept- Oct. With a almost 4 year gestation period that puts them having babies Jan thru March. A good majority of the hogs we hunt in the marsh have a lot of Russian blood in them and we see most of the pigs out there in Jan. thru March. There are always exceptions but this is what I have found in our area.
Feral hogs will have pigs anytime of the year but it also depends on the food supply. Hogs in Agriculture country always have plenty to eat and sows have to be in good condition or they will not come into heat so that could explain why they come in heat at different times of the year.
You always hear that hogs will have three litters a year. Actually that is a little over a year. I have talked to commercial hog farmers And they say some will but not all and those are hogs that are fed the best.