I had two baby kittens that we had to put out on our enclosed porch because the mother cat had fleas and we needed to get them out to bomb our house. We kept them out there for three weeks because we had to keep bombing. When our house was finally ready for them to come back in they were gone. There is no way out of our front upstairs porch except to come through the house which was impossible without some one seeing or knowing. We have no idea what happened to them and no one could have stolen them because the porch is enclosed like I said and it is on the 2nd floor of our house. Where could they have gone. Could they have been eating bugs. I'm so flustered..

How old were they? Is the mother still there? Hadn't anyone checked on them periodically? Kittens and cats can wiggle into very small spaces. If the head can get through a space, the whole body can fit too. Check for openings along the bottoms of the walls. Or else someone opened the door and let them out.

Check for ANY gaps more than an inch or so wide. If there's any furniture, check under and inside it (if it isn't typical lawn furniture).

If they're at least 4-5 weeks, you'll need to check up AND down. They start being able to climb at that age.