Ninja-n-Bear
Site Supporter
All three of ours ate as much as they wanted and were still mostly skinny until they were over a year old. I say mostly because they’d bulk up right before a big growth spurt. 
Another easy way to add fat is to use a skin-on duck breast in your mix, if you can get that locally. Lamb is also very fatty, if they like the flavor.
If you do use pork, make sure you buy stuff labeled at least ‘natural’, as the factory farmed meat is treated with a nitrate solution that no creature should be ingesting. Same thing with turkey.

Another easy way to add fat is to use a skin-on duck breast in your mix, if you can get that locally. Lamb is also very fatty, if they like the flavor.
If you do use pork, make sure you buy stuff labeled at least ‘natural’, as the factory farmed meat is treated with a nitrate solution that no creature should be ingesting. Same thing with turkey.