Hey Nellie
Please reconsider keeping your chickens on your allotment. Firstly, they are so much fun and hugely entertaining to have in the garden and, secondly - and more importantly - I have heard so many horror stories about chickens on allotments and what the less intelligent members of our society find it amusing to do to them when no-one is around.
Sadly, the only way to keep your animals safe these days is to keep them where you can see them (and, even then, Mr Fox still manages to sneak past sometimes). I am so glad that I don't own anything that would impractical to keep the back garden (like a horse) - I'd worry myself sick!
I understand the mess and nuisance involved in breaking up a bit of the patio but, really, if you can spare the space then the back garden is, I think, a much better place for them to be. And while I'm airing my opinions (well, you did ask
), I think chickens need attention more than twice a day. Even with a pop-hole opener so you don't have to let them in and out, you still need to check for eggs regularly, give them fresh water (when it is very hot or very cold, you need to make sure it is cool and fresh/not frozen solid), give them an afternoon treat maybe and I think they also like the company!
I fenced off a corner of my lawn for the chickens and, yes, they soon reduced it to a dustbath but they have pots and the flowerbeds to fuss about in and I have been known, when visiting the garden centre, to bring them home a fresh roll of grass to trash. I cover the ground with bark chips (I don't spread them out, just dump the bag on the run in a pile and the chickens spend the rest of the day scratching it all out) and, when it gets mucky, I rake the entire lot up and put fresh down - takes half an hour tops.
Really, it would be such a shame to put them on the allotment - you'd miss out on all their funny little antics and I give it a few weeks before you're thinking they'd be better off in the garden...