Hi David, sheep would go straight through, under, between or ignore that fence
It also doesnt look like it would cope with anything leaning on it and scratching their arse either so an electric line at the ideal height for the potential residents would be a good idea.
Personally I'd stock fence it - starting from the boundary and then moving inwards to your paddocks.
Even the most even minded human risks jumping an electric fence if the distance to walk around involves a long walk to the other side - animals are the same, they'll risk it if the grass looks that nice.
If an animal is happy in a field it will normally stay but if they think the grass is greener only a physical fence will stop them from trying to reach the other side.
That said my bunch of sheepies seem to think they can go where they want - you can see the walk lines that they have taken for generations and when you try to put a fence on the way they all just gather and somehow force a way under or through any obstacle thats bodged on a sunday evening by myself.
Good fencing means less stress.
Baz