Well, we normally figure an average of 4-6oz meat per person. Some will have more and some less, of course. It's rare that absolutely everyone eats together (although a roast dinner does usually get a very good attendance

), there are two vegetarians and I'm not sure how many of the children are likely to eat much chicken. (One only really eats pizza at the moment

, two are kind of veggie but eat sausages

- well, you get the picture

)
Sounds like we'll need more than 2 birds for a roast dinner, but I'd been working on 3-4kgs per bird and mostly having chicken dishes rather than a roast. It is very hard to get info about carcase weights, which is one of the reasons I asked the question! So your sharing of your own actual experiences is exactly what I was wanting - thanks very much and please keep 'em coming!