Where do I buy straw?
For people living in Denmark and that have a car, it is easy to find some on DBA. Just type "Morten Korch Halm" and you should find plenty not too far in small compacted "balle".
They cost between 10kr and 50kr depending on how many you buy and how nice your local farmer is 😉
They are around 40cm x 50cm x 90cm and weight between 10kg and 15kg, so plan a cargo-bike or a car and perhaps a blanket to protect from straw dust.