Farmers have enjoyed good rains this year but the shares of JSE-listed food companies are down.
The FTSE/JSE food producers' index has tumbled from more than 37500 points in November to about 30000.
Nick Wentzel, chief executive of poultry group Astral Foods, whose shares have dropped from nearly R155 in December to about R100, said the sector suffering from consumers' belt-tightening.
"Households that used to eat chicken three times a week can only afford it once now. January and February are usually bad months for sales because families need to buy textbooks and they are short of money after the Christmas holidays.
"This year is worse because of the higher interest rates," Wentzel said.
Competing poultry group Sovereign's share has fallen more drastically, dropping from about R21 at the start of the year to about R10 yesterday.
Nearly all food shares dived after Sovereign issued a trading update on Friday saying its earnings would be between 35percent and 45percent lower for the year to the end of this month than for the previous year.
Sovereign said this was mainly due to delays in the completion of environmental impact assessments and start-up glitches at its new facilities. It also warned that it was suffering in a price war with importers of chicken, but according to Wentzel, there is an oversupply of chicken.
The glut should drive down prices, which is good news for consumers.