How to stop my dogs crying/barking when i am not home?

i live in a bungalow, and have 2 dogs. one 3 years old and the other is 6 months old. 2 males.(father and son) . instead of keeping them in the house while i am at work, i have got them a large playhouse/dog house in the garden, and have had to chain them to a pole in the ground. although it is strong it is very light and also they can walk around the whole garden. its only the second day of being in there so i know they need to get use to it.. but to reduce complaints of the noice what can i do. they have chews and toys, food and water with them, with a blanket etc in the playhouse too. but they still seem to moan and cry. how can i stop them?