Foraging or did they abscond?

I am participant of a program that educates the public and starts them with honey bees. Most if not all of the bees were swarm donations. I was given a small swarm that we found out later had no queen. So about 2-3 weeks past and instead of giving me a new queen, they decided to set me with a second swarm that had one frame of honey with it, and about 3 or 4 drawn comb. I imagine the lady put them in the nuc box during the night when they were all there, but when I got it it was thrumming with life when I put it in the hive at home. It had a ton of bees. She had given no special instructions I was just under the assumption I would be merging the two groups side by side.

The old swarm was on the right side of the box, and the fuller new swarm I placed middle and left with the larger frame of honey in the center. I did not smoke them as they all seemed pretty docile, and one thing I remembered I did not do was bump them into the box. When I got done it seemed fine, and even at 10 today dad said it was full of bees flying around it. However, when I took a peak about 1 or so it had way less bees inside. We do have a lot of elder coming into bloom, but I didn't see any bees on the edge of the grouping of elder. They could have flown to the center of the group (About 200). So I am wondering is it normal for that many to forage or do you think they may have absconded, leaving all their drawn comb behind?

I am afraid to check too much as they may leave regardless, but would a large portion leave to forage?

Sometimes swarms abscond, although not usually once they have started caring for brood. Was the frame they were on their own brood, or added to them when they were caught? I've never really worked out what makes some swarms decide to leave, but if they don't like the conditions you have put them in then they will swarm again. They might have found sharing a box not to their liking.

Most times the bees will stay with the brood & the honey. Don't panic.

I like to spray some mint scented sugar water on all the bees before mixing them together. By the time they get over that cheap thrill they are no longer strangers.

As long as some bees are still in the hive, I wouldn't worry a great deal, most likely they are out foraging, it sounds to me like your swarm(s) were still pretty smallish.
Like Mike Barkley brought up, you need to give two swarms a way to become one collective.
When two separate swarms meet, one will almost always go elsewhere unless there is something (like the mentioned mint scented sugar water sprayed on them) to get them to cooperate.