Cooking anything especially with animal fat is NOT a good idea if you want a truly good season on your Dutch Oven.
To get a really good season follow the directions with it. Pre seasoned pans are generally NOT seasoned well enough.
Heat the pan to about a low medium heat with NOTHING in it.
Add some good vegetable oil, coat the bottom and sides very well. Pour out the excess.
Put in the oven at about 150 or 200 deg. Do not let it smoke.
watch it carefully and add another layer of oil as needed and let the pan "cook" for at least an hour or more.
Repeat this process over a couple of days.
THEN DEEP FRY something in the pan like shrimp or onion rings with plenty of oil as your first cooking in it.
DO NOT WASH WITH SOAP! or hot water in fact best if just wiped clean.
This sounds like a lot of effort but it will pay for itself time and time again...in fact everytime you cook in it.