i don't have pine trees here, but oak leaves are starting to fall, & i'll be putting some in my chickens' runs -- my set-up has enclosed henhouses up above a run, so i can just sweep the dirty bedding (pine shavings) down onto the floor of the run, which have from 4-10" of deep litter going (shallower in the newer pens still) -- and i've just bought some compressed pine pellets, to try instead of shavings -- will report on how well they work!