The Hidden Key to Healthy Puppies: Why Humidity Matters in Your Nursery

When setting up a nursery for newborn puppies, breeders generally focus on warmth and cleanliness; but there's one environmental factor that’s often overlooked and just as critical: humidity.

Maintaining the right humidity level in your puppy nursery isn’t just about comfort. It plays a direct role in puppy hydration, respiratory health, skin integrity and the dams wellbeing. In my breeding program here in the Southern Highlands of NSW, I aim to keep nursery humidity in the sweet spot: between 55% and 65% relative humidity. This range supports neonatal development while helping to prevent the issues that can arise from air that’s too dry or too damp.

What Happens When Humidity Is Too Low?

Low humidity (anything under 50%) is surprisingly common in artificially heated environments or during dry winter months. Even mild dryness can create serious problems for newborns, including:

• Dehydration: Newborn puppies already lose moisture quickly. Dry air accelerates this, leading to weakness, weight loss, and poor growth.

• Respiratory stress: Dry air irritates a puppies tiny airways and nasal passages. Puppies may struggle to breathe or show signs of congestion or laboured breathing.

• Dry skin: You may notice crusty noses or flaky skin, which can open the door to infection.

• Dam discomfort: If the air is dry, the dam may pant, drink excessively, or avoid nesting close to her puppies.

Dry air tends to 'pull' moisture from everywhere, puppies, bedding, even the dams milk output can be affected.

What If humidity is Too High?

On the other end of the spectrum, high humidity (above 65–70%) creates its own problems:

• Increased risk of infection: Bacteria and mould thrive in damp environments.

• Poor air quality: High humidity traps ammonia from urine, causing eye or lung irritation in pups and dam.

• Overheating: Warm, humid air can feel stifling, especially to the dam. She may become restless, pant excessively or avoid the whelping area, which in turn affects the puppies.

• Wet bedding: Even if it seems dry, high humidity can leave bedding feeling clammy and cold to pups, affecting their body temperature.

The Goldilocks Zone: 55%–65% humidity

In my nursery, I aim for 55% to 65% relative humidity, which provides:

• Enough moisture to support respiratory and skin health

• Low risk of mould or bacterial growth

• A comfortable environment for both the dam and the litter

• Supports stable hydration levels for the puppies

Humidity and temperature work together. As the temperature rises, so does the airs capacity to hold moisture, so a room at 30°C may need more active humidification than one at 22°C to achieve the same relative humidity.

My Nursery Setup

I’m based in the NSW Southern Highlands, about 420m above sea level, where the climate is often cool, damp and misty, much like the English countryside. The two bedrooms I use for puppy nurseries are naturally cool and prone to dampness. When the rooms are not in use, I actually need to actively monitor them for mould growth, and I keep windows and doors open to encourage airflow and reduce the environment mould thrives in. Each room opens directly onto the garden, which makes this easy when the weather permits. During the Winter months, when my puppy nurseries are not in use, I generally need to run dehumidifiers in these rooms, to remove the excess moisture in the air.

However, when the nursery is in use, things change, as the nursery doors and windows remain closed, and heaters are in use 24/7. Puppy nurseries are often poorly ventilated by design, as you want to avoid cool draughts entering the room and chilling young puppies. And then the heat from the heaters alters the air temperature and humidity. In this closed environment maintaining the right humidity becomes even more important.

To manage this balance, I use a combination of:

• Column heaters and convection heaters, which provide consistent warmth without drying the air excessively. This has the added benefit of helping regulate humidity naturally.

• Digital hygrometers placed in multiple zones of the room to monitor real time humidity levels accurately.

• Use of ventilation between litters: windows and doors are opened fully when the room is not occupied to clear out stale, damp air and improve long term air quality.

Noting, I do use space heaters, also referred to as portable electric heaters (the small, cheap heaters that blow out hot air). But I limit use of these to a short period of time when I need to quickly heat up a room, ie a whelping is occurring sooner than I predicted. I don't use this style of heater long term, as they dry out the air, use more electricity, and are a fire risk when used continuously (My father was a Fireman, so I have had education on fire risky appliances drummed into my upbringing!)

Because I’m starting from a naturally damp environment, I usually don’t need to add humidity, instead, I focus on warmth and air circulation to keep things balanced. And when the heaters are in use, I rarely need to utilise the dehumidifiers.

Final Thoughts

Temperature gets most of the attention in puppy nurseries, but humidity is just as important, if not more so, for newborn puppies. It can be the difference between a thriving litter and one that struggles with respiratory issues, weight gain or dehydration. Once you begin actively monitoring and managing humidity, you’ll notice the difference in your puppies’ wellbeing.

As breeders, we have the power to shape the environment these little lives begin in. Humidity is one of the most overlooked but effective tools we have, and it costs very little to get right. If you're setting up a nursery or fine tuning your environment, I highly recommend making humidity part of your checklist. Your puppies, and your dam, will thank you for it.