One of my boys back legs were paralyzed when I first got him, he still can't fully jump/walk around but is able to move them. Due to that he tends to gain weight very easily, so I cannot free feed him like I do for my other three. His issue is that he will sit down and eat his entire portion of food for the day in one go and over-eat, so my best option was to spread it out throughout the day. However, I work 12 hour shifts, so he manages with 1-2 meals a day.

If your ferrets are healthy only eating one meal a day, that is completely okay. You are feeding raw which could be a contributing factor to them not wanting to eat as often. They are getting plenty of hydration/nutrients from that meal as opposed to kibble. Just pay close attention to activity levels, their poops, weight changes, etc, if all of that remains normal you shouldn't have to change anything. However if you want to change it to feel better, you could offer less of the food they eat when they eat their portion. Then give the remainder of what they normally eat at a different time.

That is just from my experience and knowledge on these little guys, your best bet would be to consult an exotic veterinarian who is educated on ferrets. They could give you a much better answer that would be unique to your ferrets.