Dear Neethu,
I know the reason for their qutiting. I think, you expect those team members working in the night shift, to work continually in the night shift, right? what I mean to say, those people have to regularly report at particular time in the night and wind up their office in the next day morning, am I right? Throughout their career, that is what you are expect them to do, right?
If you answered my question "Yes", you will never be able to get rid of this problem.
Solution:
You form A, B, C shifts
A shift - 6.00 a.m. - 2.00 p.m.
B Shift - 2.00 a.m. - 10.00 p.m.
C Shift - 10.00 p.m. to 6.00 a.m.
Certain No.of people who come in A shift this week have to come in 'B' shift next week and 'C" shift next next week. Which means they need to come on rotation. 'C" shift person this week will report for duty in 'A' Shift next week. By doing so, you will ensure there is allways shift rotation.
I dont say that there will not be any absenteeism, but it will not be alarming. It will well be within your capacity to handle.
As far as your employees are concerned, in desparation of getting some employment, they will say yes for the night shift, only to gain breathing time to search for a new job. You are also fuelling their efforts by conveniently putting them in the night shift, so that they can attend interview in the next day without having to apply for leave or something. After a couple of months, they find a job of their convenience and vanish, and that is what happening.
Hence, try out "Shift rotation" model.
Balaji