This is true about the pyramiding. I heard that if the tortoise is consuming the rabbit pellets that they tend to have shell problems. I bought my leopard tort and he has slight pyramiding at 7 months of age. He has always been on rabbit pellets. I changed his substrate today to chopped hay but also a mixture of topsoil, peat moss and sand. I think the rabbit pellets also made it very awkward for him to get around. He seems to be enjoying it much better and it is also much easier for him to settle into when he sleeps.
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Lisa 
1 Mali Uro - Matilda
1 Leopard Tort - Herman
1 Shih Tzu - Jake
lisasmith@optonline.net
Monroe, NY