Salmon farming is a multibillion-dollar industry in Norway, which is Europe's largest producer of farmed salmon.
In the UK, the use of animal by-products, such as chicken, in fish feed was banned until 2013 over fears that it could spread disease to fish farms.
It has also been a sensitive topic for consumers, Margareth Øverland, a professor at the Norwegian University of Life Sciences, told the Financial Times.
"This is a very sensitive issue. Consumers have historically been very skeptical. But the market seems to be more ready now," she says.
One of the largest players, Lerøy Seafood Group, told the newspaper that it has introduced animal products at its facilities. Another, Mowi, is about to do the same in both Norway and Scotland, according to information obtained by the Financial Times.
One of the main reasons is that it is more cost-effective than traditional fishmeal, with costs estimated to be halved. It is also seen as better from a climate perspective.
Salmon are carnivores and eat other fish in the wild, so giving them chicken is completely natural, an unnamed company executive told the newspaper.