Hi
Do you have some sheets of damp newspaper on the very top ?
Worms seem to like to live under something and usually by having paper / cardboard over the top keeps them happy.
Make sure that the wormery isnt too wet, and that there isnt any smell (ie that the worms are trying to get away from something)
if no problems then just leave them as they are - worms have strange habits !!
And yes the worms are fine to pick up in clumps
Regards
Ronnie