Research & Insights
Brewer's Yeast in Laying Hen Diets: Egg Output, Shell Quality and What the Trials Show
Published
In short: published trials have fed whole Saccharomyces cerevisiae yeast to laying birds at 1.5 to 8% of the diet. Results on egg output range from clear gains to no change. The more consistent signals are better feed conversion, better nutrient digestibility, lower yolk cholesterol and, in older flocks, stronger shells.
This brief is for layer nutritionists, feed mill R&D teams and ingredient buyers in the EU, UK, Australia and the Americas. It sets four trials side by side, explains the unit each one uses and turns the evidence into a stepped trial design.
Why are layer nutritionists looking at yeast?
A laying hen turns feed into close to one egg a day for more than a year. Small changes in digestibility, gut health and shell quality add up across a flock. Late in lay, shell quality often becomes the main economic problem, because thinner shells mean more cracked and downgraded eggs. Hassanabadi et al. (2025) open their study with this point. They describe broken-shell eggs in aged hens as a large loss for the egg industry and test whether S. cerevisiae can help through intestinal health and oviduct function.
Brewer's yeast brings protein, B vitamins and cell wall compounds such as beta-glucans and mannan-oligosaccharides (MOS) in one ingredient. Our MOS and beta-glucan guide explains what the cell wall contributes. For a layer formulator the question is narrower: at what level does whole yeast earn its place in the diet, and which egg traits should a trial measure?
What do laying trials report?
| Study | Birds and age | Yeast and levels | Main reported result |
|---|---|---|---|
| Abd-Elsamee, Shalaby and Ali (2007), Journal of Animal and Poultry Production | 900 Hy-Line White hens, 24 weeks old, 16-week trial | Inactive and active dried S. cerevisiae at 0, 2, 4, 6 and 8% of diet | Higher egg production and egg weight at most levels; lower feed intake and better feed conversion; better protein and fat digestibility; shell thickness mostly unchanged |
| Yalçın et al. (2008), animal | 240 Japanese quails, 10 weeks old, 18-week trial | Dried brewing yeast at 0, 1.5, 3.0 and 4.5% of diet; isocaloric and isonitrogenous diets | No change in egg production, egg weight, feed efficiency or shell thickness; lower yolk cholesterol at 3.0 and 4.5%; lower serum cholesterol in all yeast groups |
| Elkaiaty et al. (2019), Egyptian Poultry Science Journal | 180 ISA Brown hens, 40 weeks old | Dietary yeast at 0, 0.2, 0.4 and 0.6% | Egg production, egg weight and FCR unchanged; lower feed intake; heavier, thicker and stronger shells at 0.6%; lower yolk cholesterol |
| Hassanabadi et al. (2025), Veterinary Medicine and Science | Shaver White hens, 105 to 116 weeks old, 12-week trial | S. cerevisiae yeast extract at 0, 1, 2 and 3 g/kg | At 3 g/kg: laying rate 76.9% vs 67.4% and FCR 2.75 vs 3.15 for the control; shell thickness 0.384 vs 0.362 mm across yeast groups |
The four studies do not test the same product. The 2007 and 2008 trials used whole dried yeast at percent-of-diet levels, the form closest to dried brewer's yeast. The 2025 trial used a yeast extract dosed in grams per kilogram, which is a different product with a different cost and role. The 2019 trial dosed yeast at 0.2 to 0.6%, closer to an additive level. Read each result with its unit before comparing suppliers' claims.
What can a buyer conclude, and what not?
- Egg output. Gains appeared in the 2007 hen trial and with yeast extract in very old hens. The quail trial and the 2019 hen trial found no change. Expect the response to depend on flock age, the base diet and how much room the control diet leaves.
- Feed intake and conversion. Three of the four trials reported lower intake or better conversion. This is the most practical number to track in a commercial trial, because it moves feed cost per dozen eggs.
- Shell quality. Shell effects showed in hens from 40 weeks and in hens past 100 weeks. The younger flock in the 2007 trial showed little shell change. Measure shell thickness and breaking strength, not only cracked-egg counts.
- Yolk cholesterol. Lower yolk cholesterol appeared in the quail trial at 3.0 and 4.5% dried brewing yeast and in the 2019 hen trial. Some egg brands may value that story. It needs local trial data before it supports any claim on pack.
- Dose response. In the 2025 trial, hens on 1 g/kg laid at 59.6%, below the control at 67.4%, before the 3 g/kg group moved ahead. Responses are not always linear, so test more than one level.
How should a layer trial with brewer's yeast be designed?
- Pick the flock stage. If shell quality is the target, use hens past peak, from about 40 weeks of age.
- Test at least two levels of whole dried yeast, for example 2% and 4% of the diet, in line with the 2007 and 2008 trials. Keep the diets isocaloric and isonitrogenous.
- Run at least 12 weeks after adaptation. The trials above ran 12 to 18 weeks.
- Record laying rate, egg weight, egg mass, feed intake and FCR every week. Record shell thickness, breaking strength and Haugh unit every four weeks.
- Add yolk cholesterol if the egg brand wants a quality story.
- Re-balance amino acids on a digestible basis. Brewer's yeast is rich in lysine, while methionine usually needs support from other ingredients. The amino acid profile guide gives the numbers.
Broiler teams can use the same stepped logic. Our broiler starter brief covers the meat-bird side, and the poultry guide lists inclusion rates by bird type.
Which documents do layer feed buyers ask for?
Layer feed buyers in the EU and UK check feed material status, contaminant limits and supplier certification first. Australian and Latin American mills usually start with the specification sheet, a certificate of analysis and a trial quantity. Our feed regulations guide covers the EU Catalogue entry, the AAFCO definition and labeling.
TBESBY dried brewer's yeast for layer feed
TBESBY is made from fresh brewer's yeast supplied by international breweries in Vietnam and drum-dried at our own facilities in Vietnam. The process is receiving, drum drying, milling and sieving, packing, with laboratory testing. The specification is 40 to 46% crude protein, moisture below 10%, ash below 6%, fat max 0.5%, fibre max 1.5% and lysine 30.5 g/kg, with a 12-month shelf life. Packing is 25 kg bags or 600 to 1,200 kg jumbo bags. TBESBY is U.S. FDA registered, certified to ISO 22000:2018 and non-GMO.
The full specification is on the product page. Global standards. Direct from our own facilities.
Frequently asked questions
How much brewer's yeast can a laying hen diet contain?
Published trials fed whole dried yeast at 1.5 to 8% of the diet without reported harm to performance. Abd-Elsamee et al. (2007) recommended 2% inactive dried yeast for hens; Yalçın et al. (2008) found no adverse effects up to 4.5% dried brewing yeast in laying quails.
Does brewer's yeast improve eggshell quality?
In older flocks it can. Elkaiaty et al. (2019) reported heavier, thicker and stronger shells at 0.6% yeast in 40-week-old hens, and Hassanabadi et al. (2025) reported thicker shells with yeast extract in hens past 100 weeks. Younger hens showed little change.
Is yeast extract the same as dried brewer's yeast?
No. Yeast extract is a refined fraction dosed in grams per kilogram. Dried brewer's yeast is the whole cell, used at percent levels as a protein source with cell wall compounds. Compare trials only within the same product type.
Which egg traits should a yeast trial measure?
Laying rate, egg weight, egg mass, feed intake and FCR every week, plus shell thickness, breaking strength and Haugh unit every four weeks. Add yolk cholesterol if it matters to the egg brand.
Sources
- Abd-Elsamee, M.O., Shalaby, A.S. and Ali, A.M. (2007). Using yeasts in laying hen diets. Journal of Animal and Poultry Production, 32(4), 2433-2443. https://doi.org/10.21608/jappmu.2007.219482
- Yalçın, S., Erol, H., Özsoy, B., Onbaşılar, I. and Yalçın, S. (2008). Effects of the usage of dried brewing yeast in the diets on the performance, egg traits and blood parameters in quails. animal, 2(12), 1780-1785. https://doi.org/10.1017/S1751731108003170
- Elkaiaty, A.M., Badran, A.M., Bayoumi, A.A., Eshera, A.A. and El-Sayed, O.A. (2019). Effect of dietary yeast supplementation on productive performance, eggshell quality and lipid profile of laying hens. Egyptian Poultry Science Journal, 39(2), 567-578. https://doi.org/10.21608/epsj.2019.39774
- Hassanabadi, A., Aalipour, H., Zarghi, H., Salehan, M. and Gharedaghi, R. (2025). Effects of dietary supplementation with Saccharomyces cerevisiae yeast extract on production performance in aged commercial laying hens. Veterinary Medicine and Science, 11(5), e70517. https://doi.org/10.1002/vms3.70517
Planning a layer feed trial? Ask for the specification sheet and a quote.