Forage Impacts on Poultry Meat and Egg Quality05 November 2013
A multitude of customer experiences reinforces the claim that pastured poultry is different from birds raised indoors. 'Pastured Poultry Nutrition and Forages' from the National Sustainable Agriculture Information Service (ATTRA) examines the evidence.
One of the main marketing points that pastured poultry farmers use to sell their products is that their meat and eggs are different from those produced by confinement-based poultry. While some critics dismiss these claims, a multitude of customer experiences reinforces the claim that pastured poultry is indeed different.
As pastured poultry production fills an ever-larger niche, research is beginning to explore claims of different nutritive profiles for pastured eggs and meat. In the case of eggs, evidence is emerging that the poultry products from grass-fed flocks tend to have less cholesterol, more vitamins A and E, multiplied omega-3 fatty acid content, and a healthier ratio of omega-3s to omega-6s.
Rybina and Reshetova found that egg cholesterol decreased as alfalfa (lucerne) and grass meal increased in a hen’s diet (1981). A steady increase in egg vitamin A and carotene content was observed as the amount of grassmeal increased in the diet of a flock (Davtyan and Manukyan, 1987). A study at Penn State demonstrated that hens with access to good pasture had eggs with at least twice as much vitamin E and omega-3s, as well as more vitamin A, as eggs from hens with no access to pasture (Karsten et al., 2010).
Another study, with funding from the Sustainable Agriculture Research and Education (SARE) program of the USDA, examined eggs from pastured laying flocks in Pennsylvania. The pastured eggs tested had one-third less cholesterol, one-third more vitamin A, and nearly triple the amount of omega-3s (Gorski, 2000). Lopez-Bote et al. also found increased omega-3 content in eggs laid by free-ranging hens (1998).
These studies bolster an independent study that tested eggs from 14 pasture-based farms across the country. Vitamins A and E, omega-3 fatty acids, beta-carotene, saturated fat and cholesterol were all tested and compared to the nutrient qualities of a standard production egg. The vitamin E, omega-3 and beta carotene contents were all significantly higher — in fact, more than twice as high — as those in eggs produced by chickens in confinement with no access to vegetation. The vitamin A content was higher as well (Long and Alterman, 2007).
It is worth noting that there are conflicting studies and industry claims that free-range eggs have little or no difference from eggs produced in confinement. The problem, though, is that 'free-range' simply means having outdoor access, without stipulations on the amount of time, pasture condition, minimum space requirements, or even whether the birds have access to the ground.
The results of poultry meat production on pasture are similar. Studies have shown elevated omega-3 levels in meat from pasture-raised broilers as well as higher levels of vitamin E although no difference in cholesterol (Ponte et al., 2008a) and other nutritive factors (Gorski, 2000). Pastured poultry meat may possibly have a longer fresh product shelf life (Sun et al., 2012a), as well as a discernible difference in taste according to a 30-person untrained tasting panel (Ponte et al., 2008b) although there was no significant difference among the meat qualities affecting taste as measured by the researchers in the laboratory. Sun et al. (2012a) also reported higher vitamin E and iron content in thighs and breast meat from broilers reared in grasshopper-rich alpine pastures, as well as lower cholesterol and a higher omega-3 fatty acid content (Sun et al., 2012b).