Meh.. He looks thin.. And he is under weight I think.. But resist the urge to feed more than 5-7 % body weight.

You "could" try giving 7 % for the first and last feeds of the day.. And 5% for the others..

He has been sick .. So I doubt his weight is your fault. Just keep in truckin. But take it slow with him . The last thing your gonna wanna do is give him over feeding diarrhea .. Which causes stress and that can cause the Coccidia to rear it's ugly head.

So slow and steady. He will gain on 5%. Your going what.. 3- 3.5 hours between feeding ? And he is on a good formula?

He will gain.. Slow and steady. Has his weight changed since he started feeling better?