When I talked to fisherman from the sardine fishery, sometimes they mention their preoccupation about the sardine price in relation to chicken.
They said that chicken was getting continuously a lower price at the stores, and that it was difficult to compete with it and make people to buy sardines.
But...
Can we compare both productions systems?
Moreover,
Can we compare the quality of protein and animal welfare of both foods?


Here it is a very interesting study about Life Cycle Assessment of broiler chicken production in Portugal.
It is based in data from Portugal and applied to the Portuguese food consumption.

In Portugal, 75% of chicken meat consumed is broiler chicken and it is the most consumed meat in the country. 

When comparing the global warming potential (GWP) of chicken production systems with those of pork and beef production systems, considering a functional unit based on the same protein supply (168.4 g), the production of broiler chicken had the lowest GWP. 

However, an alternative protein source from fish such as sardines (Portugal occupies a leading position in terms of hauls and consumption) presented better results in terms of greenhouse gas (GHG) emissions, with reductions of up to 88% in comparison with chicken. 
However, the availability of sardines for consumption is limited throughout the year due to fishing protocols.