I'm clueless, shelter for 4 chickens ?

[Catsanddogs]

Accidently acquired a rooster & a chicken & will get 2 more friends for him. Never kept chickens.They can free range on a safe enclosed 300 sq metre area. Rats, mice & maybe the venomous brown snake ( hope not) the only likely visitors.What kind of shelter will they need ?
Height, width, off the ground ?
Some trees, bushes, climate 10C to 45C degrees so dont want them to fry in summer. Have lots of wood, metal poles, galvanised iron & hardiplank/villa board cladding, tree branches around so can construct.
They dont have to be locked in at night.
What can I build thats simple but wont look tatty ?

 

[leghorn dude]

well the area for them to range sounds awsome check where it says coops near the top of the index page and look at the small coops lots of awsome ideas there

 

[digginchicks]

A chicken tractor might work nicely for you