Large coils for RFID

I have built a 6" diameter coil with about 42 turns that detects the key fob tags very well over a larger area than the supplied coil.

I tuned it with a 'scope to give 41 volts peak to peak. It sees the tags horizontally at about 7 cm in the centre and sees them over the wire if the detector coils planes are vertical

I intend to use them to detect when chickens enter their nest boxes so the various coil orientations are an advantage.

I wonder if others have tested larger coils - can we share designs?

Has anyone tried pet passport tube shaped tags with the RFID kit?

Has anyone seen moulded chicken leg tags offered for sale? - I use the key fob type at present!

Dear customer,

Hope you can get your answer here.
And we are welcome to sharing your project here.

Best regards,