My dogs poops can be runny toward the end of it and I think its mainly due to the (as gross as it is) as further as it is inside the warmer it is and more unpacked from being in the intestines. So sometimes at the end of the duke, it can be runny, but as long as if the duke is a majory firm, I would not sweat it.
Also the higher quality of food you feed the less duke you get. If you feed crap in a bag, these are less ingredients that the dog will asorb and making more waste to come out the other end. I feed Raw, and I hardly get more than two small dukes a day, They are also nice and firm, and do a great job of cleaning the anal sac too.
**Ok, that was somewhat of a gross post, but hope it explains what you are looking for

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