Exactly what it sounds like, I know this is just a visual bug, but it is a little annoying. It seems like it would be relatively easy to fix, just needs some cross mod communication with TAN. If the thirst could be below the horse health that would be nice, it just needs to move the horse health up an extra level if TAN is detected when minecraft loads up during initialization. A config option shouldn't be necessary.

Heres a screenshot depicting the issue:

I beleive @Adubbz is the correct person to notify here.

TAN can fix this on their end by registering RenderGameOverlayEvent.Pre for HEALTHMOUNT, and moving it up a bit when the food bar is enabled (GuiIngameForge.renderFood)

Ok I'll let him know then