size & hair length

Question
We are considering adopting two puppies from the Humane Society.  They are
a chihuahua/jack russle & beagle mix.  About how big will they grow (one is
the runt, the other the largest of a litter of seven)?  And what kind of hair will
they have (length/texture) when they are full grown, they have medium length
soft fluffy hair right now and they are about 10 or 11 weeks.  We were also
told they would not be great "walking dogs" as they will tire quickly and then
need to be carried home - is that just true now, or always?  Thank you.

Answer
Well it's hard to even predict how large a purebred will be,and even harder for a mix-same with how there hair will be,it will probably be either short a little bit wired coated

Chihuahuas cannot walk long distances,but jack russles and beagles can walk for very long distances,so again it could be in the middle