How natural sunlight affects pet and backyard ducks

Last Updated on February 14, 2025 by Susan von Frank

Sunlight plays a crucial role in the health, behavior, and egg-laying cycles of pet and backyard ducks. Understanding how light exposure affects ducks can help backyard duck keepers provide better care for their feathered family members.  

Backyard duck keepers vs commercial egg producers: different management approaches

Before we dive in to sunlight’s effects on ducks, we want to first share an important aspect of our duck keeping philosophy so you can consider whether you want to take a similar approach.

In commercial duck egg operations, artificial light is provided in order to maximize the number of eggs each duck produces per year. That’s because ducks need 10+ hours of daily light exposure in order to maintain egg production, an impossibility for animals living inside metal warehouses were it not for artificial lighting. 

However, egg laying takes a huge physical toll on a duck’s body. Therefore, pushing ducks to produce the most eggs possible each year will lead to higher rates of illness and injury, in addition to shortening their lifespans.

To offset this problem, commercial egg operations cull and replace their animals every 18-24 months. The operation’s aim is maximizing profitability, not maximizing the healthspan, lifespan, and quality of life of the animals. And that’s one reason why grocery store eggs are cheaper than backyard eggs. 

If you are a backyard or pet duck keeper, you’re probably going to take a sick duck to your vet rather than kill it. Thus, using artificial lights and diets that maximize egg production is not an ideal approach. 

That’s why we encourage you NOT to boost the egg production of your ducks by using artificial lighting. As such, this article details how natural sunlight affects your ducks throughout the year and does not delve deeply into the varying effects of artificial lighting.  

6 ways sunlight affects your ducks 

Below are six ways that sunlight affects the health and behavior of your ducks throughout the year: 

1. Social / Emotional / Immune Health 

Researchers have found that white, red, and blue light provided in artificial settings can have differing effects on poultry body weight, stress levels, immune response, and egg laying performance. Thankfully, natural sunlight contains all colors of the visible light spectrum, with variance by time of day, season of the year, and geographical location.  

Ducks’ biological systems are exceptionally well-tuned to natural sunlight. Like humans, ducks also need sunlight to feel and function optimally. Broadly speaking, ducks with access to sunlight are going to be happier, healthier, more sociable ducks than ducks raised under artificial lighting.  

As one *study summarized:

“… birds kept under natural light during day showed higher frequencies of eating, drinking and preening behaviours. While birds kept entirely under artificial light showed higher rates of sleeping behaviour. The birds kept under natural light showed heavier final body weights while the other production parameters were not affected. Moreover, birds kept under natural light showed significantly better gait score and lower incidence of tibial dyschondroplasia [bone disease]. Furthermore, natural light was found to significantly decrease the levels of serum corticosterone indicating lower stress levels.”

*Note: Some of the studies linked above were conducted on chickens, but we see no reason why the same findings wouldn’t apply to ducks and other poultry species as well. 

2. Egg production and cessation

Seasonal sunlight levels trigger hormonal shifts in ducks. As total daylight hours increase to 10+ hours per day in late winter or spring (depending on where you live), your ducks’ reproductive systems will be stimulated to “turn on” via hormonal shifts.

Younger ducks are more sensitive to the sun’s effects than older ducks. At this point in the season, you’ll also notice your ducks (even in an all-female flock) begin mating. 

The opposite effect is seen in late summer through fall when egg production and mating behaviors cease.    

Tip: If you have a duck who has been laying eggs for longer than you deem healthy, is experiencing egg binding, and/or having other reproductive health problems, you can force them to go broody in a dark environment in order to halt egg production. See: How and why to make a duck go broody.   

3. Sperm production and “gonadal regression”

If you have drakes (male ducks), you’ll notice that they are very sexually aggressive for most of the year. That’s why we keep our drake physically separated from our females for about 9 months of the year. If you have multiple drakes with females around, you’ll also need to keep your drakes separated from each other so no injuries occur while fighting for dominance.

However, from mid-November through mid-February, our drake is calm enough to be fully incorporated into the flock by day and night. This isn’t because he’s trying to be good to earn presents from Santa. Rather, his behavioral shift is due to seasonal “gonadal regression.”

Natural hormonal shifts triggered by lower light levels and secondary factors like cold weather essentially shut down his reproductive system and sex drive. Concurrently, a drake is effectively neutered during this time window since sperm production is greatly diminished.

Interestingly, research seems to indicate that male ducks are even more sensitive to light-induced gonadal regression than females.      

Tip: Do you have a particularly aggressive drake that you need to calm down? If so, you can “light neuter” your drake by putting him into a totally dark enclosure for 14-18 hours per day for 7-14 days (or continue the process to maintain a calmer state indefinitely). This can be as simple as putting them to bed early and letting them out late – just make sure the enclosure is dark. Light neutering tricks their bodies into a wintertime physiological state. 

4. Temperature management 

Ducks are remarkably adaptable to a wide range of temperatures. And since the sun dictates the temperature, you might expect some interesting temperature management behaviors from your ducks depending on the season and weather. 

Winter 

Ducks grow their own water-resistant down coats, which makes them quite tolerant of cold weather. This coat is comprised of three types of feathers::

• flight feathers, the large feathers that would help them fly (if they weren’t bred to be flightless);
• contour feathers, the smaller exterior feathers which give them their distinctively cute duck shape;
• down feathers, the smaller fluffy insulating feathers underneath the larger flight and contour feathers.    

Thelma the duck pointing to her flight feathers.

By winter, ducks should have already undergone a “nuptial molt,” wherein they have an abundance of down feathers and are looking most beautiful so as to pair up with a mate for the following year. (This is when drakes from sexually dimorphic breeds get their bright green head feathers.)   

Same drake, different seasons. Sir Winston Duckbill in January in his vibrant, sexy nuptial plumage (left) and still in his eclipse plumage in September (right).

Related: Duck molting – what, when, and why it happens

To keep warm in the winter, ducks will also spend a lot of time in the sun. While sleeping, they’ll turn their heads backward and tuck their bill under one wing in order to warm the air.

If the ground is freezing cold, they’ll either get in the water or spend a lot of time sitting down in order to keep their feet warmer. Alternately, they’ll also stand on one foot and tuck the other foot into their feathers. This one-foot tactic is due to a really fascinating heat-conserving adaptation called “rete mirabile,” which you can read more about in our amazing duck facts article.  

Summer

By summer, ducks will have removed a significant percentage of their down feathers to help with cooling, especially female ducks who have gone broody and pulled out feathers to line their nest. 

In the summer, your ducks need access to shade and swimming water to cool down. When it’s really hot out, you might notice your ducks:

• fluff up their feathers to let heat out and allow better air circulation around their bodies;
• droop their wings slightly to allow trapped heat to escape; 
• pant to dissipate heat. 

Even though our ducks have access to a large pool and abundant shade, we’ll still put out fans and a sprinkler on the hottest summer days to help them cool off.   

Related: 

• Winter care tips for ducks
• Summer care tips for ducks

5. Feather health and egg shell quality 

We’ve already talked a bit about molting, which is largely triggered by seasonal changes and daylight hours. But sunlight is also hugely important for ducks because they use it to synthesize their own vitamin D. This then works synergistically to help them absorb calcium, which ultimately allows them to have strong bones and strong egg shells. 

Here’s how: 

• Ducks have a gland at the base of their tail called the uropygial gland, which produces an oily substance. If you watch a duck preening itself, you’ll notice them rubbing their heads and bills over this gland, then rubbing their head and bills all over their feathers in order to oil themselves. 
• The oil produced by their preen gland contains vitamin D precursors which are converted to vitamin D3 when exposed to sunlight.
• When they’re preening with their bills, they use their teeth-like lamellae to scrape and mold their feathers. In addition to cleaning and maintaining their feathers, the preening process also allows them to ingest vitamin D3, which is the most bioavailable form of vitamin D. (Vitamin D2, which is produced by plants and fungi, is less bioavailable.) 

In short, sunlight improves your ducks’ feather health, vitamin D uptake, bone health, and egg shell quality!

The yellow color on Piper’s white feathers is due to her spreading oil from her preen gland across her feathers. We jokingly refer to this as our ducks “buttering their biscuits,” and Piper has some lovely biscuits.

6. Daily routines 

Ducks don’t wear watches, but they do watch the sun. They know when you’re late letting them out of the coop in the morning or late putting them up at night.

Pretty much any routine your ducks get into (and they love their routines) is closely dictated by the sun. Be warned: if you’re late, you’re going to hear about it from a flock of quacking ducks that do not appreciate your tardiness.

Also, most mammalian predators start coming out at dusk, as do owls. So if your ducks are free-ranging or out in a fenced yard rather than an enclosed run, we’d recommend you get them into their coop at least 30 minutes before sundown to reduce the likelihood of predation. We’d also recommend you NOT let them out before dawn for the same reasons.  

Now you know how and why natural sunlight helps optimize your ducks’ health and quality of life. We hope this understanding helps you make better informed decisions about your flock’s care! 

Be sure to check out the latest duck articles from Tyrant Farms!