my wiskey is only 15 weeks old and we are also hit or miss with our recalls, she will generally always start coming but how far can be debatable at times.
what i do that works like a charm is i squat down and throw my arms out like i was going to get a big hug and say come and wiskey always comes to this it is very inviting for her and i praise her like crazy once she gets to me. once she sees me squat there is generally no hesitation because i am at her level for kisses and good pettings. i would recommend this.
i bet it would work.
this is how i taught wiskey to come to me when i first started training her and sometimes she just needs the reminding by me squatting still.
i do think you are expecting a bit too much from her to come at 7 weeks old everytime, but she will come alot more by doing this i promise
ps i expected alot off wiskey too when we first got her and pushed her too much too soon but i found with this technique she was always happy to come to me.