HX711 and 3 load cells
The HX711 has two inputs, A and B channels. This would support two load cells. 

If three load cells are needed then you could put on load cell on each HX711 or two load cells on one HX711 and the last load cell on the A channel of a second HX711

You will need two HX711's minimum

If you combine two load cells on one HX711, both bridges Vcc are connected to Avdd and the sense± to INB+ and INB-