Yes it damages property so it is vandalism.
Vandalism isn't always a felony, plus shooting a paintball gun isn't necessarily illegal. It depends on the circumstances.
No.
As long as you shoot it on your property at your property.
If you only shoot your property, on your property you will be fine.
No. Because, in order for you to shoot them you would have to get their permission to shoot them. If you accidentally shoot somebody inside your backyard without their permission, it is their fault for being in the yard with someone that has a paintball gun and is shooting it in the first place.
If you have the equipment, yes. Although you may want to ask if it's legal.
In this state it is illegal to shoot a gun inside the limits of any incorporated municipility. It is illegal to shoot a gun across any road. It is illegal to shoot toward any house. It is illegal to shoot toward any person. It is illegal to shoot without a license other than at a range or for a child under the direct supervision of an adult with a license. It is extremely easy to get a hunting license. The state makes a whole lot of money from people walking around with a gun who do not have a valid hunting license. It also makes a whole lot of money from the resale of their guns. You can get good deals at the public auctions. Whether or not it is legal to shoot from your back yard depends on where your back yard is and what is behind it.
Show a picture of those pigs.
its a marker, not a gun. So technically if there are gun laws they don't apply to paintball markers. Now if there were laws against painting, then no you couldn't. But then again the paintballs have biodegradeable stuff in them and are not considered paint. Are you trying to ask if you can expel dishsoap in your yard with a dishsoap marker? That's what it sounds like to me.
pigs
Move
it all depends on the situation. if you are at a field and you signed a waiver forum then probably not but that form isn't worth much in court. But if you make the sport look bad and shoot at people, animals, and things around the neighborhood then you will go to jail for discharging a firearm (yes, in certain areas if you use a paintball marker or a Airsoft gun at non-designated areas you will be charged as if you were shooting a real firearm)
there was a petition passed that made airsofting illegal in public but it is legal to play on private property so you can play in your yard if you want