No, it's not normal. The only things I can think of is too low a temperature (can't digest the food, so they throw it up), or maybe a heavy parasite load.
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Torey
Eugene, Oregon, USA
1.2 Saharan Uros (Joe, Arthur, and Hitch)
3.0 Mali Uros (Spike, Turtle, and Tank)
1.1 Ornate Uros (Scuttlebutt and Shazzbot)
1.2 Collared Lizards (Ripcord, Thiamine, and Riboflavin)
1.1 Housecats (Roscolux and Jenny)