Natural fly traps

[chickndays]

Are there any successful fly traps and bait that are chicken-safe? Attracts and traps flies but still allows dead flies to be eaten by chickens?
Is this a thing??

 

[talkinboutchickens]

I think with most natural traps that you can make, they all involve the flies falling in some sort of liquid so I don't think chickens would be able to eat those flies (at least I wouldn't give the flies to them.)
But here's a screenshot that I took of an idea that I saw online.