Are there not waterers or feeders in with the chickens? Are they grown chickens? Can you find out if they were free ranged? Chickens need feed, water and a safe area so predators won't get them. At night they need to sleep in a place that is safe from predators because once they go to sleep anyone or anything can easily pick them up and do whatever.
These chickens have obviously been living here so if you feed them, water them, put them in their coop at night, collect their eggs daily they should be okay. Are there some feed bags around so you can figure out what they have been eating. If not hens need laying pellets or crumbles; a mixed flock (different ages) needs flock builder and oyster shell calcium for the hens; if they are young chickens they need starter. The feed store can help you. Rural King,
Tractor Supply, Co op and feed stores are places you can buy feed. You may be able to let them out during the day and put them up at night. They can eat what they want and will return to the coop about sundown. If you can find some eggs I recommend you put them in a pan of warm water. If any float to the top, carefully throw them away (they are too old and not safe to eat.) If they lay or sit on the bottom of the pan they are safe to eat. Break one and notice the yolk color. It will be darker than the yellow of a store bought egg. If it is very dark orange yellow they probably are free ranging and it should be safe to let them out during the day time.
I would not worry about their housing and roosts right now. They have been living there and are used to it. It will be easier if there are boxes with clean straw or other nesting material for them to lay their eggs. If they don't have those then you need to figure out where they lay the eggs and worry about trying to get them to use nests later.
It would be wise to know what kind of chickens you have if you plan to sell them. You can take pics and post here, look at pics on here or elsewhere online. Or you check books or hatchery catalogues to figure out what you have. If you really don't want them or care you can advertise on here or on craiglist, etc and someone will take them off your hands.
If you hang around here you will realize we love our chickens. They can pets and very entertaining. In addition to supplying eggs and being edible, they eat lots of bugs and weed seeds.