[Womble]

And don't use bark chippings - not sure about hens but they are poisonous to ducks.

I don't know anything official about this, but all I can say is that ours are still very much alive after six months rooting around in bark. (Obviously if anyone knows any different, I'd love to know  ). There are some pictures of our set-up on this thread, which may be of interest.

Cheers!

[doganjo]

I was told that by a duck breeder - it's something to do with the chemicals in treated wood that is used to make the bark chippings.  Perhaps it depends on where you get them?  She also said ducks were more inclined to try to eat the bark and could choke on it.  Don't know if that's true or not but mine could in theory have access as there is really old bark at the bottom of the bank at the end of the front paddock.

[shetlandpaul]

are you thinking of saw dust/shavings bark tends to be stripped before any cutting and preserving.

[doganjo]

no, she said bark.  I do know the difference 

[shetlandpaul]

odd. unless its the resin in the pine bark.

[doganjo]

I wished I'd asked now - it was about 8 years ago I got my first ducks.