Beautiful colours in this and would love to see one. Its not the ISO, I checked and that's at ISO 200 and the fence is fairly sharp. So I also think its been done with your pp where those details have gone. Try posting this one again, because I think it might all be there.
I'm heading on 60 and shooting with a 500mm hand held, it is getting harder so I sort of know the felling. My solution is to shoot higher shutter speeds. The cameras now days you can shoot easily with ISO 400 (APS-C) or ISO 800 (FF) and not notice much at all. Steve, a guy I shoot with uses well over ISO 1000 on FF and I mean well over, that's to get those higher shutter speeds. With APS-C, I don't like going over ISO 800 max for bird shots.
Anyway favourite subject, but try decent sunshine and a higher ISO along with maybe higher shutter speeds to compensate for those hands. Its tough I know.
All the best and these are a beautiful little one.
Danny.