You don't need a CPH number for poultry at all - it's for the four legged variety. I'm just in the process of registering as a poultry keeper as I'll go over 50 this year and although they ask for a CPH number, it's not obligatory. Which is fortunate because I got ours over a year ago and have no idea where I put it (the advice to leave it until you need it would have been pertinent in my case!).