Deborah is the hoggie expert on this site but I’ll kick in my two cents because I’ve had trouble in the past. T
1) If you mean that your hot spot is set to 80 degrees, that’s way too low. You’re going to want to bring that up to at least 88. Ambients may also be a little low at 76, but definitely fix the hot spot.
2) If she has been eating every 3 days and she is a year and a half old, there is no way she would fit in a 2.7qt tub. What are you feeding her? If you only got her when she was a year and three months old, the breeder must have been starving her based on her size comparison to the 2.7qt tub.
3) Hoggies generally like smaller spaces, so putting her in a bigger tub while she’s having feeding issues will probably make things worse.
I think bringing up the temps will get her back on track.