I currently use hemp but I am aware of the 'dangers'. They seem to really enjoy snuggling down in it and I have never seen them eat it or have I found it in any their poos.

They do however have soil and sand outside.

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I'm not biased, I don't care who beats St Helens

I have used all of the mention substrates and prefer sand soil mix , I do have in some areas hemp coating the sandsoil mix and in other enclosures I use beech chips never had any problems with impaction from anything substrate wise .

D