Worried about pony - advice please!

[PomPomFeathers]

Have had my pony for 18 years, he is now 23 (shet X Welsh A). He has always preferred working and gets grumpy if he isn't doing anything so have a wee rider for him (once a week). In the last few weeks he is like a different pony. he is hyper and aggresive and has turned into a 'bad pony'. He doesn't listen when being ridden and takes the mickey, he has lashed out at other humans in the field. He chases off his field mate (ears flat back, quite nasty) and he is charging round the field.
He is perfectly healthy to look at, you'd never know his age. No arch in back, good coat etc. He has fatty lumps in his neck but this is a problem I've never been able to fix and doesn't seem to bother him. He's just not the pony I've had for 18 years and I wonder what is going on. The girl's mum has decided to give him up so thought I would try and retire him (take him out for walks with my youngster etc) but not sure if this would set him back more? We are moving yards at weekend and he is going to be back in with my youngster again (who's a big softy and just runs away so there will be no fighting, just pony being grumpy and mean).
The other night he was upset as one of his field mates was moved so I went into field with him, he continued to charge about but every now and then would come to me, charge round me, get a rub and then off he went again.

Any thoughts appreciated.

 

[Littlelegs]

Sounds like pain to me. Given how long you've had him & his normal behavior unless anything major has happened recently it doesn't make sense for it to be stress. I would get the vet to have a look, could be something simple like he's hurt his back which is making him grumpy.

 

[DuckToller]

Ponies especially old ones can form quite close friendships so is he missing his usual field companion?

I have a grumpy shetland x dartmoor, in fact grumpy doesn't really cover it, and he has been much happier since he had a smaller pony in the field to boss about. When he is the bottom of the herd, he seems to take his temper out on humans.

Perhaps having his previous companion back will help. Otherwise perhaps it could be pain related with something going on that isn't yet apparent, but there's not much you can do about that. Mine got mild colic, and was very miserable a few months ago.

I was advised to do the 5 day panacur guard treatment as it's gentle, and they have less worm resistance as they get older. He hasn't had mild colic since so I think that might have been it for mine.

 

[PomPomFeathers]

thanks guys. The girls parents have decided to give him up (because they can't be bothered) so he will have a break from riding. He can't go back with other pony as YO is evil hence why I am moving He was in with my youngster over winter and was happy enough (except at feed times when he was greedy and grumpy but that's normal for him when it comes to food!) I'm hoping he will be happier on new, quieter yard with just my youngster in field to bully lol, my youngster is a big wimp so just does what he is told! Mum is checking on him today for me as I am at work but it's such a change that I am concerned there is something underlying.

 

[Cocorules]

When I had my pony tested for cushings via vet was asking changes in temperament and was telling me about the presence of what look like fat pads. It might be worth having a blood test done.