Hi Ahmed and Mo,
For my quail I found that temperature seemed to affect the laying. When I had mine in a free to roam barn the quail had artificial light and so would lay in the winter time but if it got very cold they would go off lay for abit. Daylight hours does also have an affect as Mo said and probably more so in your country where it is warmer all year round.
Mo is also right in that japanese quail rarely go broody and rarely hatch their own eggs in my experience, however Italian quail seemed to be more broody.
If you leave the egg in, can you put a mark on it so if she lays more you know which is the oldest. If you want her to sit then leave the egg in.
If you are worried about the eggs in the heat then you could maybe get some pebbles to put in with her so she thinks they are eggs and keeps laying and starts to sit and then you can add the eggs back when you have collected 4-7 for her to sit on. Then you can store the eggs in a cooler place until you put them under her.
sara @ farmingfriends