In my experience, this is usually via defecation and results in a hairy looking, and dry, mass of fur (and as you said, rarely with uric acid/etc.). You may be giving either prey that is too large and not being completely digested, or,feeding too often, or, feeding too much (or a combination). Remember these are typically snake eating animals and even though many kings have lived long captive lives on a rodent diet, they can have periodic complications. As long as the king is active, alert, with a good feeding response, you should be fine.
Rob Carmichael, Curator
The Wildlife Discovery Center
Lake Forest, IL
>>I have a young (2 year) king that is now consistently eating rats. From time to time I find hairballs (for lack of a better word) in this animal's enclosure. I am not sure whether or not these are "regurgitated: castings similar to what whitelipped pythons produce, or if the snake is passing them in a manner similar to feces. It is always simply a 2-3" column of compact hair, never with urates or feces involved.
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>>Any clues?
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>>Thank you.
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>>KingKeeper
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Rob Carmichael, Curator
The Wildlife Discovery Center at Elawa Farm
Lake Forest, IL