Has anyone ever had a dck that ended up having hearing problems? I have just started a pair of siblings, and right away I've noticed something very strange about the younger one.

Now first, it's only his second day here, so this could just be his way of dealing with all the newness.
but-

He's 15 months old, and can walk and feed himself, but is definitely still a BABY. He's very small, doesn't speak at all, and just still acts like a 10-month-old. Doesn't play with toys, just inspects each one for about 2 seconds and then tosses it over his shoulder and goes for the next one. He's not interested in interacting with other children or myself at all, just turns away if someone tries to engage him.

What's really strange though is what seems to be a lack of hearing. If I call his name, there is no response, no head turning, no nothing. If another child yells, shrieks, starts up a loud or singing toy, he doesn't notice, turn his head or his eyes towards the sound. After I noticed this I tried clapping my hands, loudly, to one side of him or the other, and there was zero reaction. I have yet to see him react at all to any sound.

Like I said though, it is only day 2, so I'll give him some time to adjust a bit before I jump to any conclusions, but it was so obvious that little alarm bells started going off in my head.

Has anyone had to deal with a child that ended up having hearing difficulties? If anybody has any other strategies or things to watch for, I'd love the advice! Thanks!