Hi Emzybabe
Chickens and ducks - you are soooo going to enjoy them.
My advice (having had both for many years) is;
You can get "rescued" battery chickens and ducks.
Go to
Battery Hen Welfare Trust who will point you to your nearest local Rescue to have a look.
Don't be put off by how they look - feathers grow back and they will reward you 100 times over!
If you want to go for pure breeds and / or buy locally do be careful....you are right to worry if they do not seem in good condition - use your gut feeling and trust it.
Having said that there are lots of reputable people with birds to sell.
If you have a local free range egg seller (side of the road type thing) go and talk to them and ask advice - they often know of birds for sale or even have some themselves.
Ask the age of the birds and if they are laying, if you want eggs.
You may have a poultry market in the Plymouth area. I have got lots of my chickens from ours in Hereford, and gone with my gut feelings about them - never had a problem apart from a couple of Hoodlum runner ducks who had to go!!
Good luck, and start small, despite the temptation to have lots, and you will love it and get many happy hours of fun!