Some animals arrive with a history. Others arrive with a mystery. Derek turned up with both.

The call came in July. A donkey. Owners moving abroad. No arrangements made for his care. Derek, as we’d go on to call him, had seemingly spent his entire life alone. As far as anyone knew, he'd never met another donkey.

We already had our own donkey, Dolly. She'd arrived eleven years ago with her mum, and for the past two years, since her mum passed, she'd been on her own. The idea of giving them both some companionship made perfect sense. Derek would have a home. Dolly would have a friend. Simple enough.

Derek arrived in August and went straight to the vets for a check-up before his castration – a necessary procedure so he could safely live with Dolly, and to stop us getting any ‘surprises’. That's when the other surprises started.

His teeth were rotten. Badly rotten. The kind of decay that doesn't happen overnight, the kind that means he'd been living with considerable pain for quite some time. Most of them would need removing.

Then came the second revelation. The "five-year-old" we'd been told about? Fifteen. He'd gone from relative youngster to middle-aged in one examination.

After his procedures, Derek needed time to recover in isolation so we placed him in a small field adjacent to the other equines – close enough to see them, to begin understanding he wasn't alone anymore, even if he couldn't quite reach them yet.

The moment we released him into that field is one none of us will forget.

https://www.youtube.com/watch?v=g0Eo2KbqsPI

Having never heard his own kind, never known what it meant to be a donkey among donkeys, Derek did something instinctive. He breathed in as though plucking up courage, and then slowly started to bray.

The response was immediate. Every equine came rushing to the gate. And Dolly – Dolly bounced and zoomed around her field with pure joy at a sound she hadn't heard since her mum died two years before.

It's difficult to explain what it means to witness that. A fifteen-year-old donkey discovering his own voice and being answered. Another donkey recognising, after two years, that she wasn't the last of her kind after all. A connection made across a fence line, in a language we don't speak but understood perfectly.

We deal with heartbreaking situations regularly. The financial tightrope never gets easier. There are days when the weight of it all feels impossible. But moments like Derek's first bray – that makes it worth it.

He has settled in brilliantly and lives with the herd now, generally acting as Dolly's shadow. Each day he learns a bit more about what being a donkey actually means. Things that should have been instinctive, taught to him gradually by animals who knew all along.

Fifteen years he waited. Better late than never. Derek is finally the donkey he was born to be – and we love him.