[Nes]

Can an electric fence seriously harm a cat?
(I'm sure they will only touch it once)

[KSAQHA]

Well, they may lose one of their nine lives, but it shouldn't permanently hurt them. We have a knee-high perimeter hot wire charged by a deer fence charger (powerful). The dog has hit it and let out a yelp, but fine otherwise.

Birds, on the other hand, don't fare so well. We also have a lower-voltage hot wire along the top of vinyl rail and smooth twisted wire. Every once in a while, a bird will step from the fence wire to the hotwire, be electrocuted, and hang by a leg. It's really gross when I have to pull the bird off...and its little leg is left behind.

[Nes]

Oooh, thanks for that K - we're planning chickens.
Well shoot, now I don't know what to do about our fence, guess we're going to have to look a gentler zapper!

(I think we'll run a round of tape (even if it's not connected) around the exterior of the property. Cats hit it once I'm sure they won't stray again)

[Bells]

I have to pass on one thing we learned from our neighbor’s fence - DON'T use red plastic insulators! The poor hummingbirds are apparently attracted to red. She had an electrocuted hummingbird on every section of her fence.

She is a bit of a freak so we didn't want to approach her about it. One night a bunch of us played commando, snuck around and changed out all her insulators and wow no more dead hummingbirds hanging from her fence.

[Nes]

... One night a bunch of us played commando, snuck around and changed out all her insulators ...

oh my, I have tears in my eyes laughing, thanks for that one!

I love my humming birds, it took me 2 years to attract them to our current house, and we're leaving . So I'm hopping to bring them back with lovely scarlet runners. Thankfully the field already has yellow insulators!

[Zarafia]

I've seen squirrels killed by electric fences, but the cat hit the same fence and just ran for her life.
The bird thing is most often a problem when you have a hotwire running on top of a board fence. The bird lands on the board and reaches up with its beak to stabilize itself with the wire and dies. I've seen several beautiful cardinals killed this way.

[sk_pacer]

My cats avoid the fence, and when they do go under, they go under at a post, croucihing low.tails down. They also listen for the tick and if it's ticking, they generally come to the house around the fence and certainly avoid areas where the tape sags in rain only coming within a few feet before changing course (tape is too old to carry a decent charge and is just there for visibility, the real charge is on the wire)