Ok, so here they are. The two eldest (by 9 days) are sisters, and are easily distinguished by their dark colouring, with white front paws and a cream bib. Telling them apart is something else. The only difference I've been able to spot is that one of them has a tiny fleck of grey on the top of her head. They are very similar in character, but 'no grey fleck' is slightly more aggressive and inclined to nibble your fingers when she's had enough of being picked up.
They are both super-friendly, and get very excited when the hutch is open, flinging themselves at the opening and climbing out so fast it's almost impossible to get them back in again and shut the door without risking trapping one. That and their tendency to nibble hasn't endeared them to the kids, who have retaliated by not giving them names.
The other two are younger, and are also sisters (of each other, not the other two). This one - below - (which the kids have named "Pop") is a lovely silver colour, although she is darkening up as she grows older. She is the meekest of the 4, and it's easy to imagine that she's being bullied by the others as she tends to lurk inside the nest compartment when I open the hutch. Watching them play, though, it's clear that she is a little troublemaker, jumping on the others and nipping them to start a play fight.
Pop's sister - below - (named "Panda" by the girls) is the darkest of the 4. She has no white paws or bib. She is earnest and inquisitive, and may turn out to be the most conscientious worker of them all.
I am making sure to handle all the ferrets as often as possible, usually twice a day, in the morning before setting off for work, and again when I get home. This means that I have a distinctive odour, and get some funny looks from my fellow commuters on the train.
I top up their food and water at the same times. At weekends, of course, there's time to handle them more often, as well as cleaning up the mess - not just the obvious, but the food they dig out and throw round the hutch, and the bedding they've dragged out into the rain, which has turned into a soggy mush.
I'm feeding them on James Wellbeloved (20kg bag for about £45 here - if you know where to get it cheaper please let me know!). For water, I'm using a standard rabbit-type drinker, which has the advantage they can't knock it over or try to swim in it.
From previous experience, I know how easy it is to fail to lock the hutch properly, so I've used these spring clips which can't fall out.
Skye the lab is fascinated by the ferrets, and they by her. If they ever manage to meet up without the wire between, all hell will break loose!