Hank288
Adult Guinea Pig
If he is losing weight then you need to feed him as much as you can to keep him going and to keep the weight on him. I always used crushed up pellets mixed with water as my girl didn't take to the critical care. I managed to keep her weight fairly stable by syringe feeding (didn't put weight on but didn't lose much more). You need to try and feed 90mls a day for a piggy who isn't really eating so you may want to adjust if he is eating by himself (each feed usually around 10-20mls depending on how much the piggy will take). I would say with him being so small you would need to feed at least 3 times per day, more if you can. It is hard work with the ones who struggle which is why I used her normal pellets as she loved them and snatched the syringe off me rather than refusing it.
This is the syringe feeding guide Complete Syringe Feeding Guide
This is the syringe feeding guide Complete Syringe Feeding Guide