- ✓Read growth tables (weight, cumulative feed, feed conversion ratio) and adapt them to open-sided houses
- ✓Weigh correctly: when, how many birds, and where
- ✓Calculate and interpret the uniformity of a flock
What the tables say
NEXTEKCI white broiler chicks follow the same growth curves as the reference strains Cobb 500 and Efficiency Plus (Ross 308 is also often quoted as a benchmark). Their tables give the targets reached in very good conditions: controlled housing, temperate climate.
| Age | Live weight | Cumulative feed per bird | Feed conversion ratio |
|---|---|---|---|
| 28 days | 1.78 kg | 2.36 kg | 1.32 |
| 35 days | 2.52 kg | 3.64 kg | 1.44 |
| 42 days | 3.28 kg | 5.10 kg | 1.56 |
| 45 days | 3.60 kg | 5.78 kg | 1.61 |
Cobb 500 targets, males and females mixed. Source: Cobb (Cobb500 Performance & Nutrition Supplement, 2022).
In an open-sided house, in strong heat, a good farmer often reaches 70 to 85% of these weights at the same age. Example: at 35 days, the table gives 2.52 kg; a result of about 1.8 to 2.1 kg is therefore a good result in Côte d’Ivoire. The tables are not an exam to pass at 100%: they are there to compare your weighings and to spot a delay early.
Week by week
To follow the flock step by step, the weekly Efficiency Plus table is the most practical: it also gives feed and water per day, two figures the technician can compare with the daily record sheet.
| Age | Average live weight | Feed per day | Cumulative feed | Feed conversion ratio | Water per day (approx.) |
|---|---|---|---|---|---|
| 7 days | 211 g | 35 g | 172 g | — | 60 ml |
| 14 days | 527 g | 70 g | 550 g | — | 119 ml |
| 21 days | 1,008 g | 112 g | 1,203 g | 1.19 | 190 ml |
| 28 days | 1,604 g | 152 g | 2,148 g | 1.34 | 259 ml |
| 35 days | 2,269 g | 188 g | 3,359 g | 1.48 | 319 ml |
| 42 days | 2,948 g | 214 g | 4,783 g | 1.62 | 364 ml |
| 49 days | 3,606 g | 230 g | 6,350 g | 1.76 | 391 ml |
Source: Efficiency Plus (performance objectives).
Weight at 7 days is the best indicator of the quality of the start: at 7 days, a chick should weigh roughly 4 to 5 times its day-one weight. A 7-day weight that is too low signals a flock that is behind: look straight away at heat, water and feed.
The feed conversion ratio rises with age
The feed conversion ratio (FCR) is the number of kilos of feed needed to make one kilo of chicken. In the tables, it rises with age: 1.32 at 28 days, 1.44 at 35 days, 1.61 at 45 days (Cobb 500). In other words, each extra day costs more feed per kilo produced.
That is why the selling age is decided with your own figures: a bird kept longer is heavier, but each extra kilo costs more to produce, and heavy birds suffer more from the heat. The profitability calculator on the website lets you do the sums with your own prices.
Weighing correctly
- On arrival: weigh a few boxes, about 5%, to know the starting weight. Without this figure, you cannot check the 4-to-5-times rule at 7 days.
- Every week, at the very least: always on the same day and at the same time (a bird that has just eaten and drunk weighs more).
- How many and where: about 100 birds, taken from 3 places in the house (front, middle, back). Birds near the door or the feeders do not represent the whole flock.
- Write down every weight, not just the average: the list is used to calculate uniformity.
Uniformity: an even flock sells better
A uniform flock is one in which nearly all the birds weigh the same. It sells better (buyers want even birds) and is easier to manage. You count the share of weighed birds that fall within ± 10% of the average weight.
| Birds within ± 10% of the average weight | Assessment |
|---|---|
| 80% and above | Uniform flock |
| 70% | Average |
| 60% or less | Poor: look for the cause (water, feed, space, heat, health) |
Source: Cobb.
You weigh 100 birds; the average weight is 1,600 g. The ± 10% range runs from 1,440 g to 1,760 g. If 78 birds out of 100 fall within this range, uniformity is 78%: the flock is between average and uniform. Check that all the birds have enough room at the feeders and drinkers.
For the entrepreneur
- ›Insist on a weighing every week with the list of weights, not just an average quoted from memory.
- ›Compare with the table as a percentage: 70 to 85% in an open-sided house in strong heat is a good result.
- ›Decide the selling age with your figures: the feed conversion ratio rises with every extra day.
For the technician
- ›Weigh 5% of the boxes on arrival, then about 100 birds in 3 places every week, same day, same time.
- ›Check at 7 days that the weight is 4 to 5 times the day-one weight.
- ›Calculate uniformity at every weighing and report any flock below 70%.
The 3 questions to ask your technician this week
- What is this week’s average weight, and what percentage of the table does it represent?
- How many birds did you weigh, and in which parts of the house?
- What is the flock’s uniformity, and was it better last week?
Key points
- •The tables (Cobb 500, Efficiency Plus) are targets for very good conditions; in a hot open-sided house, 70 to 85% of these weights is a good result.
- •Cobb 500: 2.52 kg at 35 days, 3.28 kg at 42 days.
- •At 7 days, a chick weighs 4 to 5 times its day-one weight.
- •The feed conversion ratio rises with age: each extra day costs more feed per kilo.
- •Weigh every week, same day, same time, about 100 birds in 3 places.
- •Uniform flock: 80% or more of the birds within ± 10% of the average weight.