What’s the Difference Between Fast Growing & Slow Growing Chickens?

Feb 20, 2023

If you’re currently raising chickens or you’re planning to start, you may have come across the term “slow growing chicken”. It’s used to differentiate from the typical “fast growing chicken”, often called meat chickens or ‘broiler chickens’ found in many supermarkets today. What’s the difference, and is one better than the other?

The short answer is that it depends on what you’re looking for. In a commercial setting, fast growing chickens are more efficient, but slow growing chickens may fetch higher prices. The debate surrounding these terms is ongoing, and it’s important to remember that this is still a developing area of interest for chicken farmers. In short, it’s much more complicated than it seems at first glance.

Below we’re going to explore what these terms really mean, and what the benefits of each are. To start with, let's take a look at the basics of raising broiler chickens for butchering.

How long does it take to grow a chicken?

Poultry products are one of the most efficient protein sources on the planet; both chicken meat and eggs are hugely popular, versatile, and healthier than many other animal products. The main driver for production efficiency is how much food and water you have to supply the chickens in order to raise them to an appropriate weight, so you can imagine why growth time is vital—the faster they grow, the less they cost to feed.

Fast growing chickens tend to mature after six to eight weeks, reaching about 3kg. Slow growing chickens, on the other hand, can take closer to around 15 weeks to put on enough weight.

How do we make chickens grow faster?

A lot of it is actually selective breeding and genetics. In other words, it really depends on the type of chicken you’re raising, rather than on any sort of farming practices you might use.

This is why it’s not so simple to define exactly what a fast growing chicken actually is. For example, all the chickens sold on the market in NZ currently are considered fast growing. This means that under the umbrella of fast growing chickens, you have a whole range of quality standards and ethical farming practices—it isn’t the case that fast growing chickens are necessarily always lower quality or live under worse conditions.

Because a lot of the science that goes into rearing chickens comes from selective breeding, farmers have also been able to select for traits that make the chickens healthier and happier, regardless of growth time. Over the last few decades farmers have aimed to breed chickens with stronger legs and better health, not just focusing on weight alone, to try to ensure size and efficiency doesn’t come at the cost of the chicken’s welfare.

The technology used to do this is getting more advanced all the time, too. Modern chicken breeders can use DNA mapping tools to select for traits like heart health, bone density, and more.

It’s not all genetics of course—farmers can also invest in better feed for their broilers, and in the environment the chickens have to grow in. The latter can be a big factor in deciding growth, as chickens need a clean, temperate area with enough space to move. Chickens placed under a lot of stress (such as those in crowded and dark battery cages) tend not to grow as well.

Are fast growing chickens bad?

A lot of the conversation revolves around the poor welfare of fast growing chickens, and animal rights activists and other critics are quick to point out that many fast growing chickens don’t behave naturally. It’s certainly true that a lot of modern broilers spend most of their time sitting, and the rest of their time moving around only to eat or drink, more or less. It’s also accepted that they continue to exhibit these behaviours even when given access to larger pastures.

In and of itself, this isn’t necessarily an issue. Genetically modified foods (GMO) and selective breeding have been common in food production for over thousands of years. Take the banana for example; it also looks very different to the way it used to thanks to selective breeding. Domesticated pets are also “not natural” in the same way—breeding for desirable traits is pretty central to human agriculture. This doesn’t mean that those arguing for better welfare for chickens don’t have a point, it’s just another perspective on the issue.

Even though the science of selective breeding is widely accepted in other areas of society, it doesn’t make a firm argument without getting deep into the major ethical discussions around whether or not we should do something just because we can. In any case, modern food production is always going to follow the drivers of the market, and chickens bred to grow larger sell better.

Animal welfare is certainly becoming more important to bigger groups of consumers. Take that same example of the banana from earlier—it’s been used as a poster child for the non-GMO debate for years. Increasing focus on nutrition and food safety over the last few decades has slowly put more pressure onto many food producers to find new ways to work. It’s undeniable that fast growing chicken breeds do have drawbacks, such as higher mortality rates, but it’s also true that there has been a big push to incorporate more welfare measures into fast growth chicken breeding.

What are slow growing chickens?

Also sometimes called heritage breeds, these chickens take longer to reach full weight. This slower growth is mostly down to genetics, but also depends on nutrition and environment. Overall, they’re generally considered to be higher quality and more flavourful.

While there is a lot of variation, slow-growing breeds do tend to be healthier. It’s more common to raise them in larger areas, and they make more use of the space than other breeds would, as they need to be housed for longer. With more time for the muscles to fully develop and more opportunity to use them, the texture of the meat they produce can be quite different, producing something that can stand apart from competitors.

What are the benefits of slow growing chickens?

These breeds do tend to have improved welfare and better behaviour, which is measured by amount of activity and lower mortality rates as compared to faster growing chickens. Studies have shown that meat quality is often better too, producing a better product for consumers. While a lot of fast growing breeders have aimed to improve quality of life for the chickens they raise, growth speed still remains a solid statistical factor in whether or not they meet the standards that critics are calling for.

On the other hand, slow growth chickens are much less efficient and fall behind their competition in almost all production benchmarks outside of animal welfare. They need to be fed a more specialised diet for a longer period of time, making them much more expensive to raise, and the major concern is that they’re unsustainable as consumers won’t want to pay twice as much, even if they do understand the benefits. A particular problem here in New Zealand is the size of the market—a small niche that is willing to pay more for a better product overseas might be large enough to support a business, but a small niche in the market here is much smaller because of our lower population.

If that niche grows however, it’s possible that slow growing chickens will become more valuable, as there’s evidence to support they can be sold for premium prices, making the added cost of raising them worth it.

Impact of slow growing on the environment

All food production impacts the environment, and the longer it takes, the greater that impact is. This leads us to another potential downside of slow growing chickens—the environmental impacts. It’s theorised that slower growth could actually have adverse effects on the environment because they use more energy and resources.

For instance, if large-scale broiler producers wanted to switch to slow-growing breeds, they would need to add more chickens in order to produce the same amount of meat. You can imagine how this could spiral out of control fast for those who want to keep their farms uncrowded. Adding more birds not only necessitates more land, it also greatly increases things such as water consumption.

This argument is interesting, because it’s true, but mostly impacts those who are heavily invested in the way they are already raising poultry, which tends to be larger battery cage producers overseas.

Slowing down fast growth chickens

One way to compromise is to raise fast growth breeds, but find ways to delay their growth in order to achieve a middle ground. Delaying growth is easier to manage on smaller farms, or for those who are raising poultry at home to feed themselves or sell at market.

Chicken growth time can be influenced by feed, as limiting protein intake can reduce how fast they grow. By rationing out smaller amounts or sticking to Chick Starter feed for longer, broilers can be raised over a longer period of time and become larger and healthier in less time than a heritage breed.

There’s a number of ways to approach this, including supplementing a limited feed allowance with scraps, making sure they have plenty of room to exercise, focusing on lower calorie feed options, and so on.

Ensuring your chickens have the best environment possible

No matter what you’re raising chickens for, or which breed you’re interested in, it pays to give them the best environment you can. After all, happier, healthier chickens live much better lives.

From smaller shelters to free-range commercial hen houses, Outpost Buildings has kitset solutions made from sustainable New Zealand timber. If you want help figuring out what coop will work best for you and your birds, get in touch with us today.

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