I adopted two year-and-a-half-old kitties yesterday (it's been about 30 hours). The two are a bonded pair and very close with one another. They have their own room set up with food (wet and dry), water, and a jumbo litter box. They immediately went to hide in the gap between the bed and wall and have not moved since. They have not eaten or drunk as far as I can tell. They peed on the blanket and carpet I had placed in front of their hiding spot and didn't use the litter box. I have left them alone, besides reading quietly in the same room for a few hours today.
I knew they were shy cats when adopting them from the shelter. I am mostly concerned that they will dehydrate and become sick if they don't eat or drink soon. I went to the store an hour ago to get the Feliway diffuser, so we'll see if that helps.
I'm reluctant to take them to a vet because I feel like it will just traumatize them more. Is there anything else I should be doing to encourage them to eat and drink?