Féchy has a population (as of December 2018) of 861.
 As of 2008, 27.5% of the population are resident foreign nationals.
 Over the last 10 years (1999–2009 ) the population has changed at a rate of 22.2%.
 It has changed at a rate of 15.5% due to migration and at a rate of 7% due to births and deaths.

Most of the population (as of 2000) speaks French (500 or 79.1%), with German being second most common (44 or 7.0%) and Portuguese being third (36 or 5.7%).
 There is 1 person who speaks Italian.

Of the population in the municipality 147 or about 23.3% were born in Féchy and lived there in 2000.
 There were 190 or 30.1% who were born in the same canton, while 113 or 17.9% were born somewhere else in Switzerland, and 170 or 26.9% were born outside of Switzerland.

In 2008 there were 8 live births to Swiss citizens and 2 births to non-Swiss citizens, and in same time span there was 1 death of a Swiss citizen and 1 non-Swiss citizen death.
 Ignoring immigration and emigration, the population of Swiss citizens increased by 7 while the foreign population increased by 1.
 There were 2 Swiss men who emigrated from Switzerland.
 At the same time, there were 5 non-Swiss men and 4 non-Swiss women who immigrated from another country to Switzerland.
 The total Swiss population change in 2008 (from all sources, including moves across municipal borders) was an increase of 6 and the non-Swiss population increased by 17 people.
 This represents a population growth rate of 3.2%.

The age distribution, as of 2009, in Féchy is; 100 children or 13.0% of the population are between 0 and 9 years old and 89 teenagers or 11.6% are between 10 and 19.
 Of the adult population, 83 people or 10.8% of the population are between 20 and 29 years old.
 100 people or 13.0% are between 30 and 39, 132 people or 17.1% are between 40 and 49, and 108 people or 14.0% are between 50 and 59.
 The senior population distribution is 102 people or 13.2% of the population are between 60 and 69 years old, 32 people or 4.2% are between 70 and 79, there are 21 people or 2.7% who are between 80 and 89, and there are 3 people or 0.4% who are 90 and older.

As of 2000, there were 265 people who were single and never married in the municipality.
 There were 315 married individuals, 29 widows or widowers and 23 individuals who are divorced.

As of 2000, there were 244 private households in the municipality, and an average of 2.5 persons per household.
 There were 61 households that consist of only one person and 16 households with five or more people.
 Out of a total of 250 households that answered this question, 24.4% were households made up of just one person and there were 3 adults who lived with their parents.
 Of the rest of the households, there are 71 married couples without children, 94 married couples with children  There were 10 single parents with a child or children.
 There were 5 households that were made up of unrelated people and 6 households that were made up of some sort of institution or another collective housing.

In 2000 there were 112 single family homes (or 62.2% of the total) out of a total of 180 inhabited buildings.
 There were 29 multi-family buildings (16.1%), along with 32 multi-purpose buildings that were mostly used for housing (17.8%) and 7 other use buildings (commercial or industrial) that also had some housing (3.9%).
 Of the single family homes 22 were built before 1919, while 11 were built between 1990 and 2000.
 The greatest number of single family homes (37) were built between 1981 and 1990.
 The most multi-family homes (6) were built between 1971 and 1980 and the next most (5) were built before 1919.
 There were 2 multi-family houses built between 1996 and 2000.

In 2000 there were 253 apartments in the municipality.
 The most common apartment size was 4 rooms of which there were 54.
 There were 13 single room apartments and 120 apartments with five or more rooms.
 Of these apartments, a total of 229 apartments (90.5% of the total) were permanently occupied, while 17 apartments (6.7%) were seasonally occupied and 7 apartments (2.8%) were empt
Féchy has a population (as of December 2018) of 861.  As of 2008, 27.5% of the population are resident foreign nationals.  Over the last 10 years (1999–2009 ) the population has changed at a rate of 22.2%.  It has changed at a rate of 15.5% due to migration and at a rate of 7% due to births and deaths.
Most of the population (as of 2000) speaks French (500 or 79.1%), with German being second most common (44 or 7.0%) and Portuguese being third (36 or 5.7%).  There is 1 person who speaks Italian.
Of the population in the municipality 147 or about 23.3% were born in Féchy and lived there in 2000.  There were 190 or 30.1% who were born in the same canton, while 113 or 17.9% were born somewhere else in Switzerland, and 170 or 26.9% were born outside of Switzerland.
In 2008 there were 8 live births to Swiss citizens and 2 births to non-Swiss citizens, and in same time span there was 1 death of a Swiss citizen and 1 non-Swiss citizen death.  Ignoring immigration and emigration, the population of Swiss citizens increased by 7 while the foreign population increased by 1.  There were 2 Swiss men who emigrated from Switzerland.  At the same time, there were 5 non-Swiss men and 4 non-Swiss women who immigrated from another country to Switzerland.  The total Swiss population change in 2008 (from all sources, including moves across municipal borders) was an increase of 6 and the non-Swiss population increased by 17 people.  This represents a population growth rate of 3.2%.
The age distribution, as of 2009, in Féchy is; 100 children or 13.0% of the population are between 0 and 9 years old and 89 teenagers or 11.6% are between 10 and 19.  Of the adult population, 83 people or 10.8% of the population are between 20 and 29 years old.  100 people or 13.0% are between 30 and 39, 132 people or 17.1% are between 40 and 49, and 108 people or 14.0% are between 50 and 59.  The senior population distribution is 102 people or 13.2% of the population are between 60 and 69 years old, 32 people or 4.2% are between 70 and 79, there are 21 people or 2.7% who are between 80 and 89, and there are 3 people or 0.4% who are 90 and older.
As of 2000, there were 265 people who were single and never married in the municipality.  There were 315 married individuals, 29 widows or widowers and 23 individuals who are divorced.
As of 2000, there were 244 private households in the municipality, and an average of 2.5 persons per household.  There were 61 households that consist of only one person and 16 households with five or more people.  Out of a total of 250 households that answered this question, 24.4% were households made up of just one person and there were 3 adults who lived with their parents.  Of the rest of the households, there are 71 married couples without children, 94 married couples with children  There were 10 single parents with a child or children.  There were 5 households that were made up of unrelated people and 6 households that were made up of some sort of institution or another collective housing.
In 2000 there were 112 single family homes (or 62.2% of the total) out of a total of 180 inhabited buildings.  There were 29 multi-family buildings (16.1%), along with 32 multi-purpose buildings that were mostly used for housing (17.8%) and 7 other use buildings (commercial or industrial) that also had some housing (3.9%).  Of the single family homes 22 were built before 1919, while 11 were built between 1990 and 2000.  The greatest number of single family homes (37) were built between 1981 and 1990.  The most multi-family homes (6) were built between 1971 and 1980 and the next most (5) were built before 1919.  There were 2 multi-family houses built between 1996 and 2000.
In 2000 there were 253 apartments in the municipality.  The most common apartment size was 4 rooms of which there were 54.  There were 13 single room apartments and 120 apartments with five or more rooms.  Of these apartments, a total of 229 apartments (90.5% of the total) were permanently occupied, while 17 apartments (6.7%) were seasonally occupied and 7 apartments (2.8%) were empt
Féchy