I hate to say it but ur mum has a serious problem!
You obviously care very much about ur dogs, but why an earth did she let you have them in the first place if she had no intention of keeping them for their whole lives.
and i mean 7 dogs in to years is a disgrace!
with ur current dog/s, if she tries to rehome them put ur foot right down and say "NO" he/she is staying here, my dog my choice,
How old are u???
Delcey