In whelp bitches don't need any extra food at first, just change her to puppy food. Then increase gradually at about 6 or 7 weeks until birth. You will have to feed her 3-5 small meals a day, as her growing babies will mean less room for food.

However, you need to get her pregnancy confirmed before you change anything. For this, you can have her scanned at around 30-35 days.

With regard to size of litters, yes, each breed does have an average number of pups. Book of the bitch says up ro 10 pups for boxers, but only gives a figure of around 6 at registration. I am not sure if this is still accurate or if boxers make clumsy/poor mothers. A friend of a friend certainly lost a boxer puppy in the time it took her to make coffee, as the bitch laid on the pups.

Have you got many bookings for pups? I think people are having a hard time selling pups at the moment, even some established breeders.