16 stone pillars 2 behemoth stone gates and 2 behemoth stone gateways and you have yourself a theri trap, put the pillars close but not to close so you can get out of the trap. Once the theri is in you have to be fast and close the gate. Once it is trapped if you have tames around it put them far away from the cage or put them on passive cause they will attack it, my argy almost died cause it was on neutral, have a ton of narcotics/bio toxin while doing this.
1. Make sure to have a metal trap, that is made of metal doors, not walls. Doors, regular doors, metal foundationa, because the tickle chickens can damage stone.
2. Make sure to make the amount of tranqdarts you need, plus an extra 20 to 30. Make sure to wait 5 to 7 seconds between arrow shots if you're using narc arrows. Which I don't advise. Use Long neck and Tranqdarts if you can.
3. Starve tame the heck out of it. And have someone nearby it's unconscious body to make sure to force feed it narcotics. Once it gets to around 1-2k food I'd toss either Exceptional kibble or kibble in first, then mejos. If you can't do kibble, just use mejos.
Side note: If you're worried about people coming and killing it in the open, just make a taming pen, at base and use a wyvern, quetzal, or skiff to move it.