The study was carried out at the University of Edinburgh's Roslin Institute and Roslin Technologies, a company set up to commercialise research at The Roslin Institute and is published in BMC Biotechnology.
High quantities of the proteins can be recovered from each egg using a simple purification system and there are no adverse effects on the chickens themselves, which lay eggs as normal.
According to researchers, the findings provide sound evidence for using chickens as a cheap method of producing high quality drugs for use in research studies and, potentially one day, in patients.
Notably, eggs are already used for growing viruses that are used as vaccines, such as the flu jab.
However, the new approach is different because the therapeutic proteins are encoded in the chicken's DNA and produced as part of the egg white.
Researchers initially focused on two proteins. This includes a human protein called IFNalpha2a, which has powerful antiviral and anti-cancer effects, and the human and pig versions of a protein called macrophage-CSF, which is being developed as a therapy that stimulates damaged tissues to repair themselves.
The study found that just three eggs were enough to produce a clinically relevant dose of the drug.
As chickens can lay up to 300 eggs per year, researchers say their approach could be more cost-effective than other production methods for some important drugs.
According to researchers, while they haven't produced medicines for use in patients yet, the study offers proof-of-principle that the system is feasible and could easily be adapted to produce other therapeutic proteins.