I'm not sure he'll eat banana. I wasn't able to get another piece to him last night. I sure tried, but he would NOT open his bill for more than a split second. I tried shoving my finger in his bill when it was open and he still twisted away. Surprisingly he didn't try to break my finger off.
But, despite not getting his dose yesterday, this morning after I let them out he went 'running' (more like flapping with his legs just barely touching the ground) across the yard. I haven't seen him do that in ages! He then proceeded to hide from me. He's mad.
When I came home today I noticed his knee was considerably smaller than it was before. He's still struggling and trips quite a bit and needs some balance over the weeds, but there is definite improvement. I decided to try a different tactic, and while he was eating his dinner I threw the piece of aspirin directly over the food. Since he's a bird he immediately went for the area the piece flew in. I checked the food after he ate and couldn't find it, so hopefully he got it. If not, the hens are much fatter and heavier than him so I doubt it will hurt them if they get it instead.
Since it's bright orange it is easily distinguishable from the grain.