Leader of pack with lots of dogs (7)
I believe the answer is:
poodles
'dogs' is the definition.
(poodle is a kind of dog)
'leader of pack with lots' is the wordplay.
'leader of' suggests taking the first letters.
'with' means one lot of letters go next to another.
'lots' becomes 'oodles' (informal term for a large amount).
The initial letter of 'pack' is 'p'.
'p'+'oodles'='POODLES'
'of' is the link.
(Other definitions for poodles that I've seen before include "Lackeys" , "Dogs in old pose" , "Curly-coated dogs" .)