There are two kinds of electric fences, solar powered and standard plug in. The solar works as long as you have enough sun to keep the batteries charged up. I would suggest getting one with enough power to run a long distance so that you get plenty of zap at a short distance. The key is to hit them hard enough the first time so that they never ever ever want to try that again.

i live in very sunny state, new mexico. so that might actually work here. thanks for the advice. :)

I would recommend you take that gun class before you buy the BB gun. You will get lots of information and you may change your mind about what to get.
In my opinion, I would never shoot a dog with a BB gun. It's not enough to kill it quickly and humanly, but it is enough to wound it and make it dangerous and it may suffer a long time and finally die.
BB guns are fun for plinking, but I would not shoot at anything living with one. I would consider that cruel.
If you want to scare them perhapses a pain ball gun. Then if you hit the culprit, you can catch him "red handed" or red painted in this case. The owner would be liable for damages in our state. Not sure what your laws are. A pain ball at close range can leave bruises, so it can hurt them but not permanent injury. I'm sure someone will have an anecdotal story about someone who suffered a permanent injury from a paint ball, but not normally, it's very rare and especially at a range of more than 5 feet. If the dog is closer than 5 feet, you are probably being attacked yourself and you have a bigger problem.
The other option is a shot gun. This has been the home protection choice of country folk for more than a century. You can choose a shell that is appropriate to the problem including less than lethal or lethal ammunition. and the shot will not travel far. Even a bb will travel quite a ways and could hit something past your target you didn't mean to hit. You still have to think about what is past your target, but shot will not travel far and does a job at close range.
Anni Oakley get your gun. Yeehaaaa
Be sure it is LEGAL to use lethal force on dogs to protect your livestock. In the city limits where I live, it is NOT legal to discharge a firearm of any sort, except in self defense.

i'm not trying to kill it right now. just keep them off the property. i need to do something now. i don't live in the city limits. one of my neighobrs uses a bb gun, too. i'm getting a cheap affordable bb gun. a gun is more of an investment and something i do want to think about. the dog that almost killed the goat lives catty corner from me and travels this way regularly. my property is one of his regular stops. so i need to disuade him from that as quickly as possible. being liable for damages is not something i could pursue here. it is gang infested neighborhood and even calling animal control around here would be bad news for me for a long time to come. you do not call any type of authorities if you don't want your house burned down. i know. i live here. it's what i can afford. so, going from that, this is what i'm thinking.

i'm not worried about someone calling the cops on me, for similar reasons. i am attempting to figure out the tone of the neighborhood and what is acceptable, what i should admit doing and what i should be completely unknowledgeable about for my own well being.

probably something like a shotgun would be what i will end up with.

people actually run over dogs and just leave them in the street here. that is the respect for life. i am considered weird for pulling them out of the street nearby my house.

how far does a bb travel approximately? like twenty feet, twenty yards, twenty ?

A lot of it depends on the gun. A good BB gun can travel 100's of yards, although it wouldn't do much damage. It would take a pretty good BB gun to penetrate a dog's hide- I was hit several times as a kid (don't ask) and it just left a red welt- never broke the skin. Depending on the dog, you could cause yourself more trouble. If you hit a pit bull with a BB gun, you're in real trouble. Some of those beasts have known to take several rounds from a REAL gun before stopping if they get in a rage. I'm worried about this myself, since I'll soon be getting my acreage ready, and there are 2 pit bulls next door that think it is their yard. I'm thinking about carrying a stun gun, with a back-up pistol if it comes to that. Once I get a good fence up, hopefully they'll stay on their own side. I'm an animal lover, but since idiots insist on turning dogs like that loose every day, I WILL defend myself and my property.

>

There is a word for people who will not stand for what is right.
There is also a word for people who have fought for what is right, some of them have lost their life. Some of them paid dearly. But they new that the price of freedom, especially freedom from the oppression of evil people, was a price worth paying. If it means putting their life on the line, then they did that. That word is courage.
When good people cower in fear and let evil like gang activity oppress them, we all suffer loss. By not taking action, you cultivate the evil and allow it to fester and flourish. The word for them is coward.
If you know who it was, if you know there are people doing evil, call the authorities and stand up for what is right. Do not spit on the graves of those who have fought and shed their blood for freedom. Be a person of courage.