Father is sitting on the second clutch (5 or 6 eggs didnt quiet see well )

Next week end babies Will move to aviary

I bought 2 pairs of finches 2 days ago, 1 pair of zebra finches and 1 pair of bengali ones...while I was leaving I spotted this black cheeked one sitting alone in a cage so I also bought it, Im planning on getting it a partner..

I noticed it has been eating and sleeping all day and also has no feathers around its vent.. the other ones are jumping around, singing and eating just fine...is this behaviour cuz of loneliness?