Using Lime on a run floor

I remember reading on here a while back, of people using lime to freshen up and sterilise thier run floors. What exactly is this lime and where do you buy it from? Also do the chickens need to be kept off it for any length of time after use? They have been in the new run about 5 months now and it needs a freshen up.

Had a look at that link, because I can see that I'll be facing the same problem in the not too distant future.
It seems to be for use in the hen house (dry), whereas I need something for the slutch that I anticipate in the hen run.
I too have heard about lime to neurtralise the soil.  Assume it's same stuff you'd use in the garden to neutralise pH and prepare bed for brasiccas.  Can buy that in garden centre.

Is it the same stuff for chicken run floors?