how long can lice get

i have just been out and checked all of my girls and de liced  single handed  that was hard work , most of them have lice again an most were quite long very skinny darkish brown things normally i have seen the little tiny brown ones { thought i got rid of } are the longer ones adults  i'm mad at myself for letting this happen but i have been checking an the last good de licing was within 1 1/2 months ago .i used up the last of my johnsons powder an ended up having to use diatom as i completey forgot that i did have louse powder left  next on my list when i get paid in a few weks time is frontline .

but theres one thing i was wandering could the wood bark harbour these bugs but the funny thing is my isa browns were clear an so was the light sussex an the 1 maran it was only the ex batts that had them???

i have some stuff on the way so dont worry i shall get even with these blighters  they will die