Just wanted to sympathise... we have had similar problems at work.
I think a lot of it is just kids these days (kids these days! Did I say that!!!)

We had a staff meeting last week where personal hygeine had to be addressed. One staff member asked did this mean he has to wash his shirt each time he wears it?
Sorry, bit OT but I think it kind of reflects the way things are, kwim?

As for asking people about their health...I don't know if it would really be of any benefit anyway. Quite possibly you would have someone tell you they are healthy as a horse, then start making excuses after a month or so...

Ah that sounds really negative... don't give up hope there are decent workers out there, one is bound to come along sooner or later