Do I need to purchase the Screw pegs separately and how many do I need?

The Omlet screw pegs are an optional accessory that you can purchase here: 

https://www.omlet.co.uk/shop/chicken_keeping/chicken_keeping_spares/9361/omlet-screw-pegs-12-pack/

You can add them for additional security against predators or if you have uneven ground. The amount of screw pegs depends on the size of your run. We would recommend 1-2 per panel.