Well, i was just comparing the ingredients between my rabbit feed and my Purina Flock Raiser, and finding them very similar, i was just about to post a similar thread to this one.
There is less salt in the rabbit feed than in the flock raiser, and since my chickens get more food from free ranging than from the feeder, i think i am going to make the switch and save $5.00 per 50lb bag.
I used to use gamebird grower feed but discovered that the only one offered by my feed store, contains antibiotics. That's why i originally switched to flock raiser, and i had to have that special ordered. So without driving a good distance AND paying substantially more per bag, rabbit food is starting to sound like a good option.
I guess if the feeder was their only source of food, i would be more concerned, but since it isn't.....