Natalie
27 Sep
27Sep

We sell a lot of fertile quail hatching eggs from our smallholding in Atherstone, Warwickshire. And one thing we've learned from talking to customers is that the single biggest variable between a good hatch and a disappointing one isn't egg quality, packaging or even the incubator brand - it's temperature accuracy.

Here is what we have discovered, and what you can do about it.

Every Incubator Needs Calibrating

This surprises a lot of first-time incubators. You buy a new machine, set it to the correct temperature and assume it's accurate. In our experience, many aren't - at least not straight out of the box.

The built-in thermometer display on budget and mid-range incubators can read anything from 0.5°C to 1.5°C off the actual temperature inside the egg chamber. That gap matters enormously when you're working within a 1°C tolerance for the entire 17-18 day incubation period.

The solution is simple: always verify the temperature independently before you set your eggs.

How We Calibrate - The Meat Thermometer Method

The quickest and most accessible verification tool is a digital meat thermometer with a probe. Here's how to use it:

  • Set the incubator to your target temperature and allow it to stabilise fully - this can take 2-4 hours
  • Insert the meat thermometer probe into the incubator at egg level - this is important, as the temperature at the top of the machine can differ from where the eggs actually sit
  • Leave the probe in place for 15-20 minutes and check the reading
  • Compare the reading to your incubator display
  • If there is a difference, adjust the incubator dial until the probe reading matches your target temperature - not the display

Do this at two or three points across the egg tray if you can, as temperature can vary slightly from one side to the other in forced-air incubators.

Other Calibration Options

A meat thermometer works well but there are a couple of additional tools worth knowing about:

Digital min/max thermometer with probe - these log the highest and lowest temperatures reached over a period, which is useful for spotting overnight drops or daytime spikes you might otherwise miss. Around £10-15 from most hardware or garden centres.

Calibrated laboratory thermometer - the most accurate option if you want to be precise. More expensive but worth it if you are incubating regularly or in larger quantities.

Two-probe approach - place two independent thermometers at different positions in the incubator simultaneously. If they agree, you can be confident. If they differ, you know there is a hot or cold spot to address.

What Happens When Temperature Is Too High

High temperature is the more dangerous of the two extremes and acts faster.

  • +0.5°C above ideal (38°C forced air) - small reduction in hatch rate, slightly earlier hatch, some chicks may pip early
  • +1°C (38.5°C) - noticeable reduction in hatch rate, increased early deaths in shell, malformations become more likely
  • +1.5°C or more (39°C+) - significant embryo mortality, deformities, very poor hatch. At this level sustained for more than a few hours, most eggs will fail

Signs temperature has been too high: eggs that pip but chicks cannot fully hatch, sticky chicks, chicks with splayed legs or crossed beaks, very early hatching (before day 17).

What Happens When Temperature Is Too Low

Low temperature slows development rather than killing embryos outright, which means the damage is slower but the impact on timing and viability is significant.

  • -0.5°C below ideal (37°C forced air) - delayed hatch, chicks hatch on day 19-20 rather than 17-18
  • -1°C (36.5°C) - significant delay, weakened chicks, poor absorption of yolk sac, chicks may struggle to hatch
  • -1.5°C or more - development stalls, late embryo deaths become common, hatch rate drops sharply

Signs temperature has been too low: late hatching, weak chicks that struggle to stand, unabsorbed yolk sacs, eggs that go full term but don't hatch (late clears on candling).

Sudden Temperature Changes - The Hidden Risk

This is the one most people don't think about until it is too late.

A sudden spike or drop - even back to the correct temperature within an hour or two - can cause more damage than a sustained mild deviation. The embryo's development is sensitive to thermal shock, particularly in the first week and in the final lockdown period (days 14-17).

Common causes of sudden temperature changes:

  • Opening the incubator lid during incubation (avoid unless essential)
  • Incubator placed near a window with direct sunlight or a cold draught
  • A room that gets significantly colder overnight - a garage or unheated outbuilding in autumn or winter
  • Power interruptions, even brief ones

Our recommendation: place your incubator in a room that holds a stable temperature day and night. A spare bedroom or interior room is ideal. Avoid kitchens (cooking raises ambient temperature), conservatories and garages.

The Right Target Temperatures for Coturnix Quail Eggs

As a reference:

Incubator typeIncubation (days 1-14)Lockdown (days 14-17)
Forced air37.5°C37.2°C
Still air38.0-38.5°C37.5°C

Humidity: 45-55% during incubation, raised to 65-70% at lockdown.

Always measure at egg level, not at the top of the incubator.

Hatch Rate - What to Realistically Expect

Even when everything is done correctly - incubator calibrated, temperature stable, humidity maintained, eggs rested before setting - hatch rate remains unpredictable and highly individual.

This is the nature of hatching eggs, and it is worth understanding before you begin.

Hatch rate is influenced by a wide range of factors, many of which are outside anyone's control:

  • Egg fertility at the time of collection - even a well-managed flock with a good hen-to-cockerel ratio will produce some infertile eggs
  • Transit conditions - postal eggs experience vibration, temperature changes and handling that can affect the air cell and internal structure, even with careful packaging
  • Age of the egg at setting - eggs set within 7 days of laying have the best hatch rates; older eggs decline progressively
  • The incubator itself - even a calibrated machine will have hot and cold spots, and different models perform differently
  • Turning frequency and consistency - missed turns, particularly in the first week, reduce hatch rate
  • The individual egg - biology is variable; not every fertile egg will develop to a healthy chick regardless of conditions

A good hatch rate for postal quail eggs is generally considered to be 50-70%. Experienced incubators with a well-calibrated machine, stable environment and fresh eggs may achieve higher. First-time incubators should expect variability and treat any hatch as a learning experience as much as a result.

We always recommend ordering a slightly larger quantity than you need to account for natural variation - and never judge a batch on a single hatch.

A Note on Our Hatching Eggs

All fertile quail hatching eggs from Beeswax Bay Farm are collected fresh, individually bubble-wrapped and dispatched tracked. We recommend resting eggs for 24 hours pointed end down before setting them - this allows the air cell to settle after transit and gives you the best possible start.

Browse our fertile quail hatching eggs