I agree that chicks should be tended. Things can happen!
I'd also watch out for your own safety--Things can happen! I wouldn't put an ad in the paper. People can trace your phone # to your address, and if you advertise that you will be out of town, potential burglars may watch for the opportune time.
I think a vet's office would be a good resource. I would not try to get the office to board the chicks because that would be very expensive. But vet techs/assistants generally care a lot about animals and I think there's a good chance one would be willing to help for a reasonable payment.
You might call the office and explain you're looking for a chick tender and tell them the part of town you're in. You could ask them to ask their staff and tell them you'll call back in a day to see if anyone is willing. When you call back, the vet or other employees in the office could help you get a feeling for how honest, reliable and careful the person is.
You could then make arrangements directly with the individual, and give them your address, etc. for them to come to your place to care for the chicks; or have the person maybe keep the chicks in a large cardboard box at their house while you're gone.
I'd feel a lot more secure getting a chick-tender that way. Just my ideas.
