Congratulations to you and your family - based on our own experiences this was a great solution. We are no experts but have experimented a lot. Our Bulgarian friends and neighbours were surprised with our open field shelter type pig houses - we made sure they had plenty of materials for building and filling their beds - e.g. old/new leftover
hay (which they would eat and use the leftovers) cereal straw (mainly wheat, barley, alfalfa), sunflower and corn stalks, a variety of twigs and sticks from pruning bushes, roses, mulberry, fruit
trees, acacia,
pea tree - anything really that they might eat, dig in or use - and they would throughout the year periodically rearrange, remake their bedding. Farrowing sows were definitely the most educational and entertaining and architecturally savvy bed builders.
Love the pictures too, especially what i guess is your son and pig - this is so good for making them easier to handle. My son and i actually slept with some of our farrowing sows mainly to test the temperatures in their pig houses in snow winter with temps at -11C to -20C.
Very very best wishes to you from Bulgaria for the new year and lots of continued fun and learning and successful breeding/meat processing with your pigs.
Nick, Jane & Toby