Ouch! You are supposed to release these type of birds in the morning so that they have some time to get down unless you want to fly them at night as well. They are high flier and endurance birds. The problem is that if they meet some strong wind and get blown away, they literally can get lost!
You may expect some returns tomorrow. If you are lucky you can get all of them. They might trickle in as days goes by if they accidentally went too far.
What happened to you reminded me of a beginner's mistake. Mistake one: You released them too late. Mistake two: probably feed them too much the day before so they ended up with lots of energy flying. Mistake three: You probably should have taught them how to get down with either a dropper or flags. Sorry if I am harsh, but these birds like rollers can get lost easily.
Next time give them more time. You may even feed them less so that they won't fly too long. And finally, if you can, teach them about droppers or some flag system so that if you want them to get down right away, they would.
Flagging means showing them some sort of flag to tell them to get down. Obviously, they are trained to do that. Some people might show an orange or white flag every time they feed their birds so they associate the flag with feed time. These birds can fly very high so the food whistle may not work. I don't know if they can hear that high. You can try both food whistle and showing them a flag. You are not going to use the flag to scare them to fly. It is more like a signal to tell them to go down. This flag can replace droppers. Those missing birds may still be around the area. You can try and search for them.
They may be hungry, but they still may have energy reserves. That is why if it is their first time release, some people cut the usual feed by 1/2 or 1/3 a day before. You are basically cutting their energy reserves.
Let them observe their surroundings first on that roof. Then maybe a week you can flag them up--scaring them up. Some birds are like that. They require persuasion to go up. If they want to go inside right away, then they are too hungry. Finding the right amount is an art.
all I can say is please dont encourage people to flag their bird after only having them out for a week of flying cuz that will surely get you lost birds that never find their way back ,especailly high flying breeds .. birds that are just learining to fly I would give at least a month of just letting them do what they want to to find their bearings when letting them out .. you cant expect them to just take off and start flying for hours from the start so give them a little time to get used to things around the loft an get their strength up too before you start freaking them out