How would you go about splitting a large package of liquid yeast to fit into demijohns? For example if I have a liter of yeast slury how do I slit it up for nine 14-gallon demijohns at a time
Is the 2-3 bbl the 31 gal bbl? If so, nine 14 gallon demis is 4.2 bbls.
If you do need to split, it would be best to pour the unneeded amount into a sanitized (sterile would be better) container. If the yeast is in a sealable container, pour what you need and reseal.
If I just pour it out or split it up evenly is this a good indication that the cell count will be split up evenly?
Good enough. You would need to count with a microscope and hemocytometer to be certain.