think egg is fertile bird wont lay on it

Question
QUESTION: Okay, so my bird layed to eggs and won't lay on them, one of them was cracked and got thrown away, the other was layed about an hour later. Except, in this egg is something I have never seen in any of her eggs before. It is a small circle with a dot in the middle, i think, and she won't sit on it. She has sat on all her other eggs, but these ones, and it's strange. But all the other ones wern't fertile, and she would be mad if she left the nest for a second and you walked into the room. Now she is plain out ignoring it. Could it be fertile? And we're keeping it under a lamp on a soft cusion to keep it warm. If you want i can send a pic of it to you (if i can find my camera) if you can't understand what i'm saying. lol
thanx :)

ANSWER: Hi, Jasmine,

How long ago did she lay these eggs (what date)?  Was the nest disturbed or anything, i.e., how did the other egg get cracked?  Is this a single bird or does she have a mate?  Is this bird housed inside or in a loft/cage outside?  What type of pigeon is this bird (homer, tumbler, other fancy pigeon)?  

Chrys

---------- FOLLOW-UP ----------

QUESTION: umm... 3 days ago her nest was not disturbed. the egg was cracked because she pushed it into her water bowl. i don't know if she has a mate or not, we have pigeons and doves around here, but i don't really know. She is mainly outside and flies around freely and then at night time she comes inside to go to sleep to get away from owls. she is a domestic pigeon (rock dove)

Answer
Hi again, Jasmine,

She could be laying infertile eggs and this is why she won't sit on them.  Females birds can lay infertile eggs without having mated.  If this egg was just laid 3 days ago and she hasn't been sitting on it yet, then there's no way you would know if it's fertile or not when candling it.  A parent bird that has mated successfully has to incubate an egg for about 7-10 days before an embryo/veins can be seen when the egg is candled.  What you see inside this egg is most likely the same thing you see inside an infertile chicken egg from your refrigerator...a zygote I believe it's called.  If the egg is fertile and she incubates it, the zygote will start developing into an embryo.

A fertile egg has to be kept at about 98 degrees F constantly, turned 1/2 way around every 12 hours at least, therefore, I doubt this egg will hatch being kept under a lamp, if it's fertile to begin with.  If this bird had a mate, they would both care for any eggs that are laid.  They take turns incubating their eggs...dad incubates during the day, mom at night.  Doesn't sound to me like she has a mate if she's coming back every night.  Otherwise, she'd either bring him home with her or she'd stay out with him at night.

Chrys