The message
from martin contains these words:

A hundred yards would put parts of a 4 acre site out of range?

Depends on the shape of the plot and where the henhouse is.

In the centre of a square plot, no.

At one end or corner of a rectangular plot, lots of it.

HTH

--
Rusty Hinge
horrid·squeak&zetnet·co·uk
http://www.users.zetnet.co.uk/hi-fi/tqt.htm