Back in the day when I still made wheat flour pastry I found that the best fat for pastry was about half butter (for flavor) and half "something else" (for flakiness). My mother, who learned to cook in the 40s & 50s, used margarine or Crisco. I did too initially, but then went to lard (much better!). For awhile, when I didn't have access to good pork fat for lard, I even experimented with chicken fat. It worked quite well, but, while the chicken taste was not overwhelming, I did find that it was best to use this pastry for savory pies. Chicken fat is also a great cooking fat. And, anything said about chicken fat, goes double for duck fat <yum>