The only thing that I can think of is to drill a couple of holes thru the bottom of the feeder near the corner and run a chain or cable thru it. The legs are bolted on, so unbolting the legs is easily done.

Realistically, if someone wants to steal it, they will.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).