Puppy Has Dry Skin

hi all my friend has a litter of 3 puppy's 2 are black 1 is apricot thay are 2week's old the problem my friend has is her 2 black pupp's have very dry and flaky skin thay are feeding ok putting on weight not scatching or wining she has the pupp's in a bed next to a radeator i said it could be the heat as you all know the weather has been bad and her radeator is alway's on any of you guyes got any thought's on this as we are just at a loose end as to why only the black ones have dry skin and not the apricot one any help would be gratefull thank's