I would NOT allow them near each other. Ferrets are related to weasels and their instinct will be to kill and eat your chickens and/or any other birds you may have. I have owned ferrets in the past. I had one rip my parrot out of the cage while I was in the shower and kill it. It was traumatic. Birds and weasels do not mix. You can own both, but be extremely cautious if you have your heart set on it. In the end I re-homed my ferret as I am much more attached to being a bird owner and the idea of having both the birds and the ferrets caged at all times to be safe didn't sit well with me, both birds and ferrets thrive on time out of a cage. Good luck. I am not trying to shoot down your dreams, but I want to paint a realistic picture for you. You can own both, but they CANNOT be housed together or allowed near each other, EVER.