Why Your Puppy's Good Behaviour Doesn't Last (And What to Do About It)
Posted on 14th October 2026
You had a brilliant week. Your Cockapoo was sleeping through, the toilet training was clicking, and the biting had started to ease off. You thought — finally, we're turning a corner.
And then, almost overnight, it all fell apart.
The accidents are back. The sleep is broken again. The biting has ramped up. And you're wondering what on earth you did wrong.
What you're seeing is puppy regression — and it's one of the most normal, most misunderstood things that happens in puppyhood. This post covers what's actually going on, why it happens, and exactly what to do when it does.
What Is Puppy Regression?
Regression is when a behaviour your puppy had already learned appears to go backwards. They were clean in the house — and now they're not. They were settling at bedtime — and now they're crying again. They were biting less — and now it's got worse.
Most owners assume they've made a mistake. They look back at what changed — did they let things slip? Did they give too much freedom too soon? Were they inconsistent?
Sometimes those things play a part. But more often, regression has nothing to do with what you did. It's developmental. Your puppy's brain is going through a growth phase, and the behaviours that felt settled are temporarily wobbling because everything else is shifting around them.
Regression isn't a sign that your puppy has forgotten what they learned. It's a sign that they're growing.
Why Does Regression Happen?
Puppies go through a series of rapid developmental stages in their first sixteen weeks. Their brains are changing, their bodies are changing, and their understanding of the world is expanding fast. The American Kennel Club describes several distinct developmental windows between eight and sixteen weeks — including a fear period around eight to twelve weeks, and a pre-adolescent phase from twelve to sixteen weeks where permanent teeth start coming through and puppies become more independent and exploratory.
During any of these windows, the brain is essentially reconfiguring itself. And when that happens, behaviours that were becoming automatic can temporarily lose their grip. It's not that your puppy decided to ignore the rules — it's that the rules are competing with a lot of neurological noise.
There are also physical triggers. Teething, in particular, causes significant discomfort and drives a change in biting behaviour. A puppy who was managing well may suddenly become much more mouthy — not because training failed, but because their mouth hurts and they're seeking relief.
Dealing with puppy biting?
If you're here, chances are it's happening. Take the free Puppy Biting Quiz to find out exactly where your puppy sits — and what actually helps next.
Puppy Sleep Regression: What It Looks Like
Sleep regression is one of the first things owners notice. Your puppy was settling well at bedtime and sleeping through a reasonable stretch — and then suddenly they're restless, waking in the night, or crying before they'll settle.
This usually happens around the same developmental windows mentioned above. The puppy's brain is more active, they're more alert to their environment, and their sleep architecture is shifting to match a growing nervous system.
What not to do:
- Start trying lots of different approaches at once. Changing your routine every night is the thing that makes sleep regression last longer.
- Rush in every time they make a sound. This teaches them that crying brings company — and they'll cry louder and longer next time.
- Assume something is wrong and panic. In most cases, this is temporary.
What to do:
- Stick to one consistent bedtime routine and see it through. Boring is good.
- Give your puppy the chance to settle without immediately intervening at every sound.
- Make sure the sleep environment is right — dark, quiet, comfortable, and familiar.
If your puppy was sleeping well before, they can sleep well again. Consistency is what gets you there.
If your puppy was sleeping through and it’s suddenly fallen apart, I’ve gone deeper into exactly what’s happening in My Cockapoo Puppy Was Sleeping Through and Now They’re Not.
Toilet Training Regression: When the Accidents Come Back
Toilet training regression catches owners off guard because it's so demoralising. You've been religious about the routine. You've praised every success. And then one day, the accidents start again.
One important thing to rule out first: if the regression is sudden, dramatic, or comes with other symptoms (straining, unusual urgency, accidents during sleep), rule out a UTI or other medical issue with your vet before assuming it's behavioural.
If your puppy is healthy, the regression is almost certainly developmental. Their bladder control is still maturing — full control often isn't established until around six months — and during a growth phase, the signals can get scrambled. They genuinely may not be able to hold it the way they could last week.
If you want to know what’s realistic for your puppy’s age, read How Long Can a Cockapoo Puppy Hold Their Bladder?
What to do:
- Go back to basics without frustration. More trips outside, same spot, same cue, same praise.
- Reduce freedom temporarily — use a crate, playpen, or baby gate to limit unsupervised access until things stabilise.
- Clean accidents thoroughly with an enzymatic cleaner. The scent of previous accidents draws puppies back to the same spot.
- Don't punish accidents. It creates anxiety and confusion, and it doesn't speed up bladder control.
This is a step back, not a reset. The foundations are still there — you're just giving your puppy the support they need while their body catches up.
Biting Regression: Why It Gets Worse Before It Gets Better
Biting regression is the one that rattles owners the most — because the biting that comes back during a regression often feels different to the biting you had before. It can be more intense, more targeted, harder to interrupt.
There are a few things driving this. Developmentally, your puppy is becoming more alert, more reactive, and more interested in interacting with their world. That often means more mouthing. But teething is the biggest physical driver: when your puppy's baby teeth start to be replaced by adult teeth, their mouth is uncomfortable, they're frustrated, and they're looking for relief wherever they can find it.
To see where your puppy is in the process and what’s coming next, read Your Cockapoo Puppy’s Teething Timeline: What to Expect, Month by Month.
Teething biting, frustration biting, and overstimulation biting can all look similar on the surface — but they need different responses. Getting the approach wrong won't just fail to help; it can make the biting worse.
What to do:
- Make sure your puppy has toys with different textures — rubber, rope, hard chew, soft plush. Puppies bite and chew for different reasons, and if everything in the toy basket feels the same, they'll go looking for variety. Usually on your hands.
- Rotate toys so they stay interesting.
- Manage stimulation — an overtired or overstimulated puppy bites more. More rest, less busy time.
- If the biting is intense and consistent, it's worth understanding what's actually driving it before deciding on a response.
My free Biting Quiz can help you identify which type of biting your puppy is doing and what to do about it — because the right solution depends entirely on the cause.
Supporting Blogs:
The Calm Cockapoo Evening Routine: A Step-by-Step Guide for Settled Nights
Resources:
Stop the Evening Chaos: Helping Your Cockapoo Puppy Settle, Focus, and Feel Safe
Freebies:
The Cockapoo Puppy Sleep Training Guide
Watch on YouTube
5 signs your Cockapoo puppy is overtired
The One Thing That Makes Regression Worse
The most common mistake owners make during regression is trying too many things at once.
When behaviour goes backwards, the instinct is to fix it fast — to research, to change the approach, to try something new. But for a puppy in a developmental growth phase, constant change is the problem, not the solution. Instability in your response makes it harder for them to find their feet again.
Pick one plan. Stick to it. Give it time.
The owners who get through regression fastest are the ones who stay boring and consistent when everything in them wants to try something different. That's not passive — that's strategy.
When to Get Help
Most regression is temporary and resolves with consistent management. But there are times when it's worth getting professional support:
- The regression has lasted more than two weeks with no improvement despite a consistent approach.
- The biting is causing injury or feels genuinely out of control.
- You're seeing other behavioural changes alongside the regression — fear, reactivity, significant appetite or energy changes.
- Your puppy is showing physical symptoms alongside toilet training regression (see your vet first).
If you're at that point, a single 1:1 session gives us the chance to look at exactly what's happening with your puppy and build a plan that fits. You don't have to keep troubleshooting alone.
Regression feels like failure. It isn't.
Your puppy hasn't forgotten what they've learned. The foundations you've built are still there. What's happening is that their brain is growing faster than their behaviour can keep up with — and that's not a problem you created. It's a phase you can support them through.
Stay consistent. Stay calm. Don't change the plan every time something wobbles. The owners who find puppyhood hardest are usually the ones trying the most things — not the ones doing the least.
One thing you can do today: pick the regression that's bothering you most, go back to the simplest version of the routine, and stick to it for a week before you try anything else. That's it. Simple is what works.
— Clair
Founder, Cockapoo52