'Bird' - sometimes spelt 'brid' - meant the young of our feathered friends as long ago as 800 AD in Anglo-Saxon texts, so you might find a phrase such as 'a hen and her birds'.
It was not until half a millennium later, in 1300, that 'burd(e)' meaning a �maiden' is first recorded. That was associated with 'bryd', from which we get the modern word, 'bride'. So, the connection between birds and girls/women is truly ancient...even today, in Scotland, women are often called �hen'! But, despite the claims of some, the flying ones definitely preceded the human ones.