: In this study, the effects of propolis and vitamin C (L-ascorbic acid) supplementation in diets were investigated on feed
intake (FI), body weight (BW), body weight gain (BWG), feed conversion rate (FCR) and digestibility and on egg production and
qualities (weight, mortality, shell thickness) in laying hens exposed to heat stress. A total of 150 Hyline White Leghorn, aged 42 weeks,
hens was divided into five groups of 30 hens. Chicks were randomly divided into 1 positive control, 1 control and 3 treatment groups.
The chicks were kept in cages in temperature-controlled rooms at 22°C for 24 h/d (positive control, Thermoneutral, TN group) or 34°C
for 9 h/d from 08.00-17.00 h followed by 22°C for 15 h (control, heat stress, HS group) and fed a basal diet or basal diet supplemented
with vitamin C (250 mg/kg of L- ascorbic acid/kg of diet) or two levels of propolis (2 and 5 g of ethanol extracted propolis/kg of diet).
Increased FI (p