An example provides a fluid ejection apparatus including a fluid feed slot to supply a fluid to a plurality of drop ejectors, a first rib at a first side of the fluid feed slot and supporting drop ejection circuitry to control ejection of drops of the fluid from the plurality of drop ejectors, and a second rib at a second side, opposite the first side, of the fluid feed slot supporting a thermal sensor to facilitate determination of a temperature of the first rib and the second rib.