For reliable results, you should isolate a single tribble with a single serving of food. Having multiple tribbles, multiple food types, and/or stacks of food leads to unpredictable results. It sometimes works, but sometimes you get tribbles that don't eat, and sometimes you get tribbles that eat but don't reproduce, and sometimes an entire stack gets consumed at once and you end up with some tribbles that don't match the expected type.
Just fed a 2 Griffis's 2 hearts of Targ in my inventory and after an hour one heart of Targ was gone but no tribble was produced?
I had 2 tribble, 2 heart of targ separated in inventory. Now i have one heart of targ and no 3rd tribble.
I did by these heart of Targ as a lot of 2 then separated them.. should this have happened?
For some reason tribbles get confused when you offer it more than 1 of an item. I have had 1 of every food item in the inventory and each food every hour has been replaced with a tribble without fail. Tested it out with 3 of the same food unstacked with 3 tribbles and I get 1 or 2 tribbles replacing the food they ate leaving 1 food item left. So theoretically 1 tribble may choose to not breed at all in that instance.
Ive breed about 100 or so and never had a tribble not be produced... thats strange.
It happened to me when I had a tribble, a drink, a shield charge, and a medium hypo on my action bar. The tribble ate the food but didn't reproduce. My guess is there was no room as the new tribble was supposed to spawn in, so it didn't 'reproduce'