The Gallagher comes with a battery.
Read the info links at http://www.gallagherusa.com
and other electric fence suppliers.
Most problems with electric fence is the ground. With single wire fence the ground wire from fence charger is connected to grounding rods - metal or preferably copper driven into the ground. Many get one rod to work but I have always used three rods wired together spaced 3 to 5 ft apart for the ground. With this type of set up the animal must touch the ground/soil and the wire. If the soil is wet the shock is greater very dry and it is weaker.
For multi strand fencing you can make one of the wires a ground (negative/green colored wire on the Gallagher ) and one or more the hot (positive/red wire on the Gallagher) wires. With this set up the animal has to touch both wires at the same time. I built a poultry pen out of cattle panels and was still having some problems with raccoons. I attached the ground wire to the pen panel and ran a hot wire (positive) about 4 feet off the ground the raccoons try to limb the pen to get in and get shocked when they touch the wire and the pen panel. Chickens touching the pen do not get shocked. Cows rubbing against it get shocked as they end up touching both.
With any fencing you have to fence the desire- have a in heat mare on one side of a fence and a stallion on the other you need a 10 foot high very strong fence, a 3 foot space then another 10 foot high strong fence to keep them apart. Not in heat if they have been trained to an electric fence just one wire and it does not need to be attached to a power source. One a horse, cow, pig, sheep or dog learn what a hot wire is they will never willing touch it again. I do not say goats as my goats will get a goat up against the wire then push them thru/over it. Once the wire is down they run a mock. Kind of funny but I would hate to be the goat pushed thru.
If the animals have plenty of food and water and no one is in heat or they are already together it takes a lot less to fence them in. I have seen one of my uncles use an electric fence for years without having fence charger. He bought some new heifers and picked up a charger on his way home as the new cows were not trained to the wire.
I think what you are proposing will work for poultry.
I have neighbors that have movable hoop shelters that they put a woven electric fence around to keep the chickens in. They also use herding dogs. They keep a dog in each pen to keep stray dogs, raccoons, cats, fox and coyotes out. Each pen is about 1/4 acre they move the pens a couple times a summer I suppose every 6 to 8 weeks. They have 3 of these and raise several thousand fryers this way every year.