Picked up a 9 week old kitten on Saturday and she has barely eaten since. Is this just nerves or do I ring the vet?

I know, I know. Willow is 14 and I swore I'd never do the kitten thing again, but a colleague's cat had a litter and I went round "just to look" and now there's a small tabby called Bramble behind my sofa.

She came home yesterday afternoon, about 9 weeks, with a bag of the kitten wet food she'd been on and one of her mum's blankets. Saturday evening she had a few licks of a pouch and that was it. Today, NOTHING. I've put the pouch down four times, warmed it once, tried a bit of the biscuit Willow has (I know, wrong food, I was panicking). She has come out to drink, twice that I saw, and there's one small wee in the tray, so it's not like she's frozen entirely. But she stays wedged behind the sofa and if I go near she flattens herself like a pancake.

Meanwhile Willow is sitting outside the spare room door making a noise I've never heard her make in 14 years, which can't be helping.

How long can a kitten this small actually go without food? Everyone says "they always eat eventually" but she's tiny and I keep reading things about kittens and blood sugar. Do I ring the out of hours line TONIGHT or is a day of not eating just what a scared kitten does? I feel like I've ruined a perfectly good kitten in 30 hours.

Ours did almost exactly this in June and it turned out to be cat flu getting going, so the first thing I'd do is look for sneezing or a wet nose or a gummy eye, because a kitten that can't smell won't eat. If she's clean and dry on that front it's more likely just terror. Warming the pouch and putting it right at the entrance to wherever she's hiding was what worked for us, she wouldn't cross the room for it.

But I'd ring in the morning whatever happens overnight. I've learned the hard way that a kitten's margin is a lot smaller than an adult's.

Ours ate nothing for the first day and a bit, lived under the bed, and then ate like a horse once we put the bowl actually under the bed with her. Same food she'd had at the breeder, nothing new. Do the vet call though, ours was the Alfie era and I was not a careful person then.

A kitten who has eaten nothing for a day gets a phone call to the vet today. Not because she's necessarily ill, but because a 9 week old kitten has very little in reserve, and the rule this site uses for adults, that 24 hours of eating nothing is a vet visit, tightens rather than loosens for a kitten. If she's still bright, drinking, and has used the tray, this is a call to the daytime clinic rather than the out of hours line, but it's a call, and I'd want them to at least weigh her and look in her mouth. The reasons a kitten stops eating, and how a vet approaches it, are in the site's guide to why a cat is not eating, and the kitten section of that is written for exactly this day.

On the nerves side, which is the likelier story: everything you've described is a frightened kitten doing what frightened kittens do. Hiding for the first few days is normal, and a kitten will eat behind a sofa long before she'll eat in the middle of a room with a stranger watching, so put the food where she is, not where the bowl "should" go. Keep her on the breeder's food for now, the wrong biscuit was a panic move and I've done it too, and any switch waits until she's settled, mixed in over about a week. A little warming, a shallow saucer rather than a deep bowl, small amounts offered often and taken away when refused, and the room door shut with Willow on the other side of a second door if you can manage it. Fourteen years of not hearing that noise is a good sign of how strongly Willow feels, and the kitten can hear it too. The set-up for that first fortnight is in the new kitten guide, base room and all.

What tips it from "ring today" to "go now": lethargy that's more than hiding (floppy, cold to the touch, not reacting), any vomiting or diarrhoea, or a kitten who stops drinking as well. I've settled in rescues who took months to trust me and every one of them ate within the first two days once the room was quiet enough; the ones that didn't had something else going on, and the vet found it. Your vet can look at Bramble, which is the part none of us can do from here.

Rang at half eight, nurse said bring her in at eleven. Vet weighed her (1.02kg), looked in her mouth, checked her nose and eyes, felt her tummy, took her temperature, and the verdict was "healthy, frightened, slightly cross." No flu signs at all, which was my main worry after Denise's post. Told me to do more or less what Hannah said: food at the hiding place, breeder's food only, small and often, and ring back if she's not eating by tomorrow evening.

Came home, put a warmed spoonful on a saucer literally behind the sofa, sat on the floor with a book and pretended not to exist. She ate about half a pouch while I stared very hard at the same page. First food in 40 hours. I'm ridiculous about it.

The pretending not to watch bit is real and it never really goes away. Smudge is 4 and still eats better if I'm reading than if I'm looking at her. Glad she's had a proper once over.

Day 6. Three small meals a day, eaten on the saucer, now roughly a foot out from the sofa rather than behind it. Came out last night and sat on my slipper for a bit. Willow has stopped the noise and moved to silent disgust, which I'll take. The vet's receptionist rang to check on her yesterday, which I did not expect and nearly cried at.