broody after an internal lay?

[modees]

Could our 20 week old silkie have gone broody at the same time she layed internally? We went to put her to bed one night and found her sitting on an egg which she laid at least two hours later than she had ever done before. I removed the egg and she opted to sleep in the nest box. The next morning we found a runny yolk on the ground (she's our only layer) without any signs of shell. We found this less than 18 hours after she layed her egg the night before. We took her to the vet after she spent the next four hours in her nest box panting. The vet said she couldn't find any shell and thought that she never got to the shell part of development before she pushed it out. Odd? But she did start laying at 16 weeks so reproductive problems are more likely. So for the next three days we have given her the antibiotics the vet gave us. She spends all day in the nest box resting on bedding only and pushing (or trying to push something out her vent). She leaves three or four times a day for about 10 minutes to eat and drink, dust bath.

What is this? What do we do? Is she still sore and resting from the invasive vet visit? Is she egg bound or an internal lay stuck?

any advice is so greatly appreciated!!!!!