We buy ours in bulk from the local hippie bulk food store, and they get.... 1 cup flax seed per 10LBS feed. So 2.5 cups per 25lb bucket. (yeah I had to go dig up my notes).
I am a heart patient...
Omega 3-6 gel tabs are so cheap ... I do not understand all the poohah really about the omega 3-6 eggs altho I do "share" the occasional gel tab with my birdies as a supplement in their feed along with wheatgerm oil etc.
I don't know why you feel that flax won't grow in the Ft Worth area. It grows quite well here in the Phoenix area and we are considerably hotter than you. Y'all do have more humidity, and a LOT more rain.