Both Parnaby and McFadden are free agents after their latest deals with the Blues expired but have stayed on to train with the club as they go about finding a new club.
But Hughton has revealed that the pair could be given fresh terms as he looks to improve his squad which sits 15th in England's second tier.
"I'm hoping to add in the loan market," he told the Birmingham Mail.
"We're keeping tabs on that as each day passes, seeing what openings there are.
"It can be a difficult one as there are lots of clubs in the same situation looking to bring players in. But we're trying to keep our eye on what is available.
"He's (Parnaby) training with us and we are very much looking at him," he added.
"He's a player everybody knows here, it's an opportunity for me to see him close up."
On McFadden he added: "He's been training with us for a good while now since the summer. He's one we're still assessing.
"He's training on the back, of course, of an injury - quite a big injury - and the club knew it was going to take him a period of time to recover.
"With that, it's about making sure he completes his rehab and getting into football-work.
"He's a player of very, very good ability and he has shown that in the past."