Signs of pregnancy in bitches

hello i have been breeding whippets for many years now and it is oten difficult without having them scanned to tell if a bitch has taken i have noticed it easier in maiden bitches as the teats start to swell very early even the first two weeks with older bitches often at around 21days they go off their food for a spell if anyone knows of other signs i would be glad to hear thank you
will

With some of my bitches their vulva stayed more swollen if they were in whelp, but not all conformed. To be honest with my own it was their change in temperament, that told me, they became more clingy & less independent when they were in whelp. Had one bitch who had a false pregnancy if she was mated even if she hadn't taken. Never found a way to know early with her.

The earliest sign that I thought my bitch was pregnant before I had her scanned was that my other 3 dogs were acting different around her.

thanks for that info i often thought the continued swelling of the vulva was a guide but never sure whether it was her still wanting the dog the only behavioural difference i have noted is a desire for more food
cant say ive noticed my other dogs behaving differently but its hard to tell thank you again responding to my post
will