My dog is in heat... and she and my male dog both stopped eating?

I have 2 spitz. one male and another female. the male dog is neutered.. both are almost a year old now. my female dog is in heat for the 1st time and she is having her period.i was noticing that my female dof was eating less. also my male dog. but for the last 2 days both of them has stopped eating almost. they are playful but they dont eat. egg is their fav. they didnt eat that. only thing they still eat very little is raw chicken bone. but even these they dont eat much. is it normal for dogs to stop eating during heat? they are all vaccinated and dewormned. and before these they never had any health prob. please help.