Ross 308 and Cobb 500 compared for Ghanaian farmers: who breeds them, growth pattern, feed response, legs, heat, and why management outweighs the breed name.
Halaal Farms Ghana team4 October 2026 · 12 min read
Put the two breeding companies' target tables side by side and the difference between Ross 308 and Cobb 500 at six weeks is smaller than the difference between two farms in the same town raising the same breed from the same hatch. That is the most useful thing to know before you spend energy on the question of which is better. Both are excellent birds. Both will disappoint you if they are chilled in the first week or fed dusty, badly mixed mash.
There are still real points of difference, some supported by evidence and some repeated out of habit. This article sets out who breeds each bird, what each is known for, what holds up on an open-sided farm in Ghana and how you can test the two for yourself.
Ross 308 is a product of Aviagen, a breeding company with its headquarters in the United States and part of the German-owned EW Group. The Ross name goes back to a Scottish breeding firm, and the bird is sold across Europe, Africa, Asia and the Americas.
Cobb 500 comes from Cobb-Vantress, an American company owned by Tyson Foods. Cobb is one of the oldest names in poultry breeding, tracing its history to a farm started in Massachusetts in 1916, and the Cobb 500 is its main product worldwide.
The numbers in the names are product codes. They do not stand for grams, days or anything else you can use.
Both birds are hybrids built the same way. Each company keeps pure pedigree lines and crosses them over several generations to produce parent stock, which it sells to breeder farms. The eggs those parents lay hatch into the broiler chicks you buy. Two consequences follow. A real Ross 308 or Cobb 500 chick can only come from the right parent stock. And you cannot breed your own replacements from grown broilers, because the offspring of a hybrid do not repeat its performance.
Both have been selected for the same goals: rapid growth, low feed use for each kilogram gained, a large breast and good survival. They look alike because they were built for the same job.
Each company publishes performance objectives and updates them every few years. The current tables for both breeds put a mixed-sex flock somewhere between about 2.3 and 2.5 kg at 35 days and around 3 kg or a little more at 42 days, on a cumulative feed conversion of roughly 1.4 to 1.55. Day-old weight in both guides is a little over 40 grams.
Do not try to pick a winner from those tables. The two companies do not build them on identical assumptions, and each describes what its bird can do under very good conditions: closed, temperature-controlled housing, pelleted feed made to the company's own nutrient recommendations, clean water through nipple lines and healthy chicks from prime-age parents.
Very few farms in Ghana offer all of that. Flocks in open-sided houses on mash feed commonly run well behind the tables, and that is normal. Use the targets as a ruler for your own progress from batch to batch, as described in our article on broiler weight targets, and not as a promise.
The table sums up what each bird is known for. The notes that follow explain how much weight to put on each point.
| Trait | Ross 308 | Cobb 500 | How much it matters on your farm |
|---|---|---|---|
| Early growth | Steady start | Known for a quick start | Small; brooding decides the first week |
| Later growth | Known for finishing strongly at heavier weights | Good, with emphasis on efficiency | Small to moderate if you sell heavy birds |
| Feed response | Responds well to higher-specification feed | Promoted as efficient on lower-cost feed | Uncertain; feed quality varies more than breeds do |
| Legs | Selected for leg strength | Selected for leg strength | Management matters more than breed |
| Heat | Not heat tolerant | Not heat tolerant | No proven difference |
The most repeated claim is that the Cobb 500 gets away faster in the first two to three weeks, while the Ross 308 catches up and does well when taken to heavier weights. Many growers will tell you they have seen exactly this. Published trials are less tidy. Some find Cobb ahead at 35 or 42 days, some find Ross ahead, and many find no difference worth acting on. Results depend on the feed used, the temperature, the sex of the birds and the age of the parent flocks behind each group of chicks.
If you sell light birds at about five weeks, a quicker start is worth a little. If you take birds to seven weeks or more for the live market, later growth and sound legs are worth a little. In both cases "a little" is the honest size of it.
Cobb promotes the 500 as a bird that performs efficiently on plainer, lower-cost diets, and its nutrition guide allows for feeding lower nutrient levels where that gives a cheaper kilogram of live weight. Aviagen's guidance for the Ross 308 stresses how the bird responds, in growth and breast meat, to well-balanced protein. Farmers often read this as "Cobb for cheap feed, Ross for good feed".
Be careful with that conclusion. A lower-cost diet designed by a nutritionist is still a balanced diet. It is not the same thing as mash that has been stretched with extra maize bran or mixed unevenly. Neither breed performs on feed that is short of protein, stale or mouldy. Both were developed on pellets and crumbles, and both eat and grow better on them than on fine mash. Our guide to feed conversion ratio shows how to measure what your feed is really delivering.
Lameness, water belly and sudden death are diseases of fast growth, and any modern broiler can suffer them. Both companies select for stronger legs and hearts, and neither bird is free of the risk. What reduces these losses is the same for both: a few hours of real darkness each night after the first week, dry litter, enough feeder and drinker space so that birds walk, correct minerals in the feed and avoiding overheating. If you see more than the odd lame bird, read our article on leg weakness, ascites and sudden death in broilers before you blame the breed.
You will hear that one or the other "handles our heat better". Neither was bred for it. A broiler approaching 2 kg produces a great deal of body heat and has little ability to lose it. Above about 30 °C in the house, birds of both breeds pant, drink more, eat less and grow more slowly, and on a still, humid afternoon the heaviest birds die first. The breed makes no dependable difference. House design, stocking density and the timing of feeding do, and they are covered in our guide to preventing heat stress in broilers.
Not reliably. Day-old chicks of both breeds are yellow, broad and heavy compared with layer chicks, and grown birds of both are white-feathered and heavily built. Experienced growers say the Cobb looks blockier, with a wide breast, and the Ross stands a little taller. That may help someone who handles thousands of both. It will not help you settle an argument with a seller.
This matters because "Ross" and "Cobb" are sometimes used loosely to mean any white broiler. Ask the hatchery to name the breed for the specific hatch date and to put it on your receipt. Halaal Farms Ghana supplies both Ross 308 and Cobb 500 broiler day-old chicks, and we tell you which breed a hatch is before you pay.
If the genetic difference is worth tens of grams, these are worth hundreds. They are listed roughly in the order in which they act on the flock.
A weekly routine for all of this is set out in our week-by-week broiler management calendar.
If your hatchery can supply both breeds, the best answer for your farm is the one you measure. A fair comparison needs discipline, because careless trials produce confident wrong answers.
Here is the sum at sale, with invented example figures and an example feed price of GH₵ 8 a kilogram. Use your own numbers.
| Example figures | Pen 1 | Pen 2 |
|---|---|---|
| Chicks placed | 250 | 250 |
| Birds sold | 242 | 240 |
| Average live weight at sale | 2.30 kg | 2.35 kg |
| Total live weight sold | 556.6 kg | 564.0 kg |
| Feed used | 960 kg | 985 kg |
| Feed conversion (feed divided by weight sold) | 1.72 | 1.75 |
| Feed cost | GH₵ 7,680 | GH₵ 7,880 |
| Feed cost for each kg sold | GH₵ 13.80 | GH₵ 13.97 |
Pen 2 produced heavier birds and more kilograms. Pen 1 produced each kilogram slightly more cheaply and lost fewer birds. If you sell by weight, Pen 2 brought in a little more income for a little more feed. If you sell at a flat price for each bird, Pen 1 did better. A gap this small could reverse in the next batch, which is why one trial should never decide the matter. The poultry profit calculator will take these figures and show the margin for each pen.
For many farmers the practical choice is made by availability: you take the breed your hatchery has on the date you need chicks. That is a sound way to buy, because a healthy, on-time chick of either breed is worth more than the "right" breed arriving late or from a seller you cannot check. When both are on offer for your date, these leanings are reasonable.
A hatchery sets the parent-flock eggs it has, so the breed on offer can change from one hatch to the next. If your last batch was Ross and this one is Cobb, or the reverse, change nothing in your house. Brooding temperatures, space, feed phases, lighting and the vaccination programme your vet has set are the same for both. Compare your weekly sample weights with the target table for the breed you have in the house, because the two growth curves are not identical in the early weeks. Write the breed at the top of the batch record. After a year you will have a fair picture of each bird on your own farm, through the rains and the dry season, without running a formal trial.
What you should not accept is a change nobody told you about. The breed is part of what you agreed to buy. A hatchery should say, before you pay, if the hatch for your date is a different breed from the one you asked for, and should leave the decision to you.
Current starting prices for broiler chicks are on our day-old chick price list (from GH₵ 20 when last checked on 2 October 2026, and subject to change). To book Ross 308 or Cobb 500 for a particular date, or to ask which is hatching that week, use the Halaal Farms Ghana order form or call 024 915 1503.
Under the ideal conditions the breeding companies describe, both pass 2 kg by about five weeks, and independent trials have put each ahead at different times. Cobb 500 is often said to start faster and Ross 308 to finish strongly, but on most farms the difference is tens of grams. Brooding temperature, feed quality and stocking density change the result by far more than the breed does.
You can, and they need the same temperature, feed and vaccination programme. Keep them in separate pens if you want to learn anything from it, with feed recorded for each pen. Mixed in one pen you cannot tell which breed ate what, and any small difference in early growth lets the bigger birds dominate the feeders.
You cannot confirm it reliably by looking at the chicks, because both are yellow as day-olds and white-feathered when grown. Ask the hatchery to name the breed for your hatch date before you pay and to write it on the receipt. A hatchery that keeps or sources genuine parent stock knows exactly which breed each hatch is and has no reason to be vague about it.
Neither has a proven advantage in heat. Both were selected for fast growth in controlled houses, and both eat less and grow more slowly when the house stays above about 30 degrees Celsius. In hot areas put your effort into house orientation, a high roof, open sides, fewer birds on each square metre and cool water, and consider selling at a lighter weight in the hottest months.
Written by the Halaal Farms Ghana team. We hatch and import day-old chicks at Opeikuma, Kasoa, and deliver to all 16 regions. This article is general guidance for farmers. For diagnosis and treatment of sick birds, speak to a vet or your district veterinary office.
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