Mobs Bug/ Feature

[Cosmo2401]

So I had a little problem while trying to fight the Chaos Dragon, I could only see him one chunk far and the rest of the fight I couldnt see him at all. Is this a feature or a bug, is there a option to see mobs from farther away or not because even with the normal ender dragon I had the problem that at some point I couldnt find him anyome.

[dirtwrap]

have you tried changing your settings for rendering distance ?