1 - Hens don't make any noise apart from the odd cluck when laying an egg.
Hens can be very noisy. They can cluck away for extended periods of time when they're unhappy and have learnt to clamour for your attention. Your neighbours WILL hear them and this may be as early as FIVE a.m. in the summer. A friend of mine was reduced to tears and eventually had to rehome her hens because of their early morning rowdiness. Their alarm call is even louder and will be triggered by foxes, cats and anything they don't recognise or feel scared of.
2 - You can move an Eglu (or other small run) around your garden every couple of weeks and stop your lawn from being wrecked.
In two weeks two hens can completely destroy an Eglu-run sized piece of lawn. It will take months to grow back. You will end up with many bare patches. Consider keeping them in a permanent spot and putting down wood chippings (from your own prunings perhaps). These can be changed regularly and the old ones composted. Make your garden hen-proof if possible and let them out for a few hours every day if you can. They'll be perfectly happy.
3 - Two hens are enough company for each other.
Except when one of them is inside laying and the one left outside goes bananas because she's on her own (hens need the security of a flock) and shouts her head off for half an hour or more. If you get three, hopefully there will always be two together and you won't have to spend your day squatting by the run calming a hysterical chicken.
