Whilst I'm sure your flock would gladly eat suet - I'd personally stay away from feeding fats to my chickens - they simply don't need that kind of energy, assuming they are getting proprietary feed. Having said that, I seem to eat fat - sure I don't need that kind of energy either, but it tastes good
As redsoxs advises, moderation is the key with any treats.
Today I hung part of the treat in their coop and they loved it. I didn't think about it making them fat. They don't have much room to run right now so I'll make sure to not give them to much. Thanks for the replys.