My three girls (Isa Browns) free-range and have been generally very healthy and happy. They went off the lay in winter and now it seems only one has started laying again (I'm wondering if it's the one not affected by what I'm about to describe). Two of them are now getting really horrible bums!! Sorry for the gross-out, but the poo is getting all caked up around their feathers just around the cloaca to the point that one of them was all blocked up with a big rock of dried poo - poor lil' chooka! I've had to trim back the poo-covered feathers and wash their bottoms under the tap (which I'm sure you can imagine they were not thrilled about), but 2 days on and it's happening again.

I've had chooks for four or five years and I've never had this happen before. It seems odd - especially in that it's happening to two of them so I'm wondering whether it's something environmental / diet related.

I will take them to the vet if it keeps up, but in the past he has been next to useless with the chooks (great with the dog though), and usually wants to refer me to a bird specialist which I can't afford. Thought I'd try here first... any ideas as to what's causing this and how I can treat / resolve it??