Nah, he's just...showing his age, I think. You have to put food right near him for him to realise it's there but his appetite in general is still strong. And then Mourne was eating Bann's hay through the bars again so I'd put down another clump of hay, turned my back and suddenly all I can hear is Mourne is going 100% on the rumble.
Turns out Bann saw me put the hay down, realised Mourne was thieving it, and ran over to push Mourne's nose up through the bars before sitting right in his new hay pile, to deny Mourne access.
Been a while since I've seen him shift like that, lol. He's clearly still got some bark to that silent bite.
(poor Mourne, lol)