Personally I would not use one for several reasons.
Apart from the cruelty issues in a multi dog household they are pretty useless if one dog barks both collars will go off so the dogs have no idea what they are being punished for. Dog 1 barks and dog 1 and dog 2 get a response from the collar. Dog 2 is very confused and has no idea why.
The dogs that do not care about the discomfort from the collar will be quiet for a day or so and then just bark regardless again. Some even learn to bark beneath the range that sets off the response from the collar.
Those that are frightened by the collar will always give you an alternative behaviour eg digging up the lawn as they are stressed or weeing in the house as they are scared to go outside because of the response from the collar. So a wasted £60.00 usually.
What you can do though is confine the dog to a smaller area of the garden. (Ironic I know) however some dogs just find a large space on their own quite exciting/scary/boring so can bark to relieve their emotions. Collies may just start runinng up and down the length of the fence for example - a bit like a stressed polar bear in the zoo.
If they have a smaller space they can feel more relaxed and less barking. Put them in the small space with something to do eg a big marrow bone to chew and a long line on them. The second they bark go outside say nothing and bring them in on the line. The go outside and remove the bone.
Do this several times a day, week etc and they will soon learn bark means come in. As they get more relaxed in the smaller bit of garden you can gradually increase the space they can have. If you are all out in the garden then obviously they can go in the whole garden.
It will take a bit of effort but you will then have the rest of the dogs life in silence 
Obviously if the dog has a bone it may be necessary to have only one outside at a time - that will depend on your dogs and their relationship to each other,
The other thing you can do is to feed them outside but just scattering their food on the ground to keep them busy again best to do one at a time.