I learned this at my other house. My 'woods pen' had lots of pines (and hemlocks, which they didn't eat...except for some of the tender new growth of limbs in spring) in it. Limbs they could hop up on got denuded of needles, especially in the winter when there wasn't much else to 'attack'. However, they would do it year round...and really liked the tender 'buds' growth in the spring of the new shoots and new needles. They have done this here, as well, to the few branches they can reach with needles on them on the 2 pine trees in the extended run. I figure if they like them, why not give them more as enrichment? I"ll have to get pics of what they do to the limbs/needles this weekend!