Long range RFID or other sensor

Hello!
I was hoping to revive this thread and take it on a tangent. I am also working to use long range UHF RFD to track wildlife, but in this case wild turkeys. I am working with a science museum on projects to connect people with urban wildlife and we want to gather data on turkeys that live on the property using an array of readers.

Does any one have advice about how to best find a suitable tag for a turkey? I was hoping there might just be a larger version of those I have seen for songbirds.

Also, I was hoping someone could fill me in on how things would change if I needed to track more than one bird simultaneously.

Thanks a lot. This forum is awesome.