Dick, the usual galvanised, chicken wire available in the USA is good
for 3 seasons near the ocean, tops... Then they turn into rust balls...
Unless your chicken farmers there near the coast have better materials
available I would be wary...
The gulls that hang around my boat will stand on anything, I doubt that
chicken wire would bother them... I also doubt that putting the mesh on
the roof will make a major improvement in signal strength, especially
if it is above the radials... First your radials are already elevated
above the ground a significant fraction of a wave which reduces ground
losses... Putting your money/energy into having 6 or 8 quarter wave
radials for each band is more likely to show a better result...

cheers ... denny / k8do