A comfy layer of straw is the best option for bedding closely followed by wood shavings.
Don't use hay as bedding though, as it contains fungal bacteria and will probably lead to breathing problems. Make sure that the bedding is changed regularly to keep it from becoming damp and dirty. Check it thoroughly for eggs before you throw it out though!
Childs, 16 April 2020
i keep runner ducks and chickens in a fenced pen with laying/nesting house at the end rats are everywhere we have tried concrete and sadly poison I would like to buy a house/coop for them 7 that is metal based and sided