Wood Preserver...

Hope this is the right place to post this (sorry if it isnt)    I converted a 6x4 shed into a coop and attached a former rabbit hutch to the side to provide nest boxes.  The shed was only about 6mths when i bought it and it is shiplap (the type B&Q sell for £149)   Anyway  I used a standard fence stain on it as one side was brand new and the other sunfade. It doesnt let water in per se but the wood does get soaked.  Can anyone recommend a good water proof stain?  I have heard 'Ducks Back' is good   but I would rather take a recommendation before I buy  Thanks in advance.

I used the ducks back for ours because it claimed to be pet safe.
http://www.cuprinol.co.uk/products/5_year_ducksback.jsp#top
But I also applied it before the chucks turned up so even if it hadn't have been okay it had a week to dry so no chance of harm.

It's quite good, but I've found that it seems to wear off quite easily. Since it seems to be a wax product that sits on the wood rather than permeating the wood itself. e.g. the roost bars and the door hatch were down to bare wood in a matter of weeks.
I also found that it doesn't stand up great to wild bird poo that ends up being on the roof. Again it seems to be because the wax just sits there.

So I'd love to know any alternatives, but it does seem to do the job.

Cuprinol's helpline is very good, and ducks back is fine for poultry.