Thank you for your input, ladies.
I think I might try the renting option first. It probably costs as much as setting one up anyway, but it feels like less of a commitment. Might ask on freecycle if someone needs a babysitter for their chooks while they are on holidays or something, that way it would be free...

I would certainly talk to the neighbours before getting chooks to make sure they are fine with it and to talk to them about any concerns they might have. The promise of free eggs might get them on board. It might also be easier if I tell them we're renting first. So they can get used to the idea while knowing it's only temporary.

With regards to the dog, I'd probably keep the chooks seperate. Another one of my concerns is chook poo everywhere... Don't want the kids covered in it constantly when out and about. Dog poo is pretty easy to pick up. Chook poo is a completely different issue. Yes, i know, it's a great fertiliser, but i just can't help my poo-phobia :-)

I was thinking if I keep them permanently, I will get one of those portable chicken tractors. That way I can take the whole thing kid and caboodle to a friend if we go on holidays...