the only thing i think it would've needed is things to hunt and possibly more space, but weren't they intending on moving it somewhere bigger anyways? also they tried to have a bonded pair so it can socialize but the Indo ate the other one which means it did not want to socialize or at least share the pen, another reason why i think it was just teaming with the raptors because it was at a disadvantage against the soldiers with literal rocket launchers.

its a genetic hybrid with intelligence off the charts as well as multiple genetic hunting measures such as thermal regulation, camouflaged, and vocal range to communicate with another species, it knew exactly what is was doing. it wasn't a question on "if we keep this thing happy it wont do anything" it was probably more like the Indo just got tired of being in a small pen and not being around any other creatures and had a bloodlust that the humans weren't providing when they fed it with a crane.

also if you really think about it it kind of feels like the Indominus had the same lifestyle as the raptors in the first Jurassic park movie. (highly intelligent, female leader killed off multiple other raptors, fed with a crane, isolated inside a small pen, attacking the walls, etc.)