Oh good friend, i'm so sorry for that.
I had a similar situation today. The main door had small holes on the down part, so i put a wood line there until they become bigger, yesterday I removed. Believe me, the last night I had a dream of some quails playing in front of that door, but outside! In the morning I run to count them and there are only 19 instead 20, My mother is still laughing about that strange story

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Probably may be similar to pheasants, I had the same situation some years ago with them and they stayed close the area, I left the door open and in a night i found them inside. You may try to put some food close to the area, to conserve they close if they are still. If you live in the camp, is a plus.
A trap may be factible, there are many alternatives in youtube.
Hope you will recover them! I'm so sorry for this terrible experience. I know how frustrating is