An emergency method of hatching them
If a hen abandons her eggs after brooding them for a number of days it is possible to rescue the eggs and hatch the chicks inside.
As an emergency, and if this is only something you would do very rarely then, no complicated equipment is needed. I would not recommend this method for valuable eggs or as something you would do on a regular basis. The idea of this method is simply to try and save a few chicks. All the eggs need are a little heat and some attention. Do not expect all of them to hatch as, even in ideal conditions with a professional incubator, this is unlikely to happen.
Place them gently in a container with a layer in the bottom of something soft like wood shavings, sawdust, cotton wool or even a piece of cloth.
A simple heat source is now required. A reading lamp will suffice or something similar with a powerful light bulb. You can purchase 250W bulbs which are ideal for this situation and for raising the chicks later, if that proves necessary. The light should be directed at the eggs. The temperature at shell level should be approximately 100 degrees F. Adjust the height of the lamp to increase or decrease the temperature. If you have a lidded box then it will help to keep the heat inside. Do not make it airtight though as they are living things and need to breath.
Word of warning – if any of the eggs start oozing a yellowish liquid, which will smell, then carefully remove them. I do stress ‘carefully’ as rotten eggs are prone to explode.
250 Watt red heat lamp
Hens eggs take about 21 days to hatch, give or take a day, depending on conditions. Hopefully you will have some idea of how long they have already been incubated. Unless the eggs are with in a couple of days of hatching they will need turning at least twice a day. You can mark them on one side with something non toxic, to facilitate this, but I have never found the need to do so. This is something the hen would do naturally. They will also need misting with a little water occasionally. I do this once a day. Again eggs would naturally receive a little moisture from the hen’s body.
As long as they were not left unheated for too long they should still be viable and will hatch. When they do begin to hatch do not attempt to help them. It may take as long as a day for a chick to hatch. Although I did witness one hatch from start to finish in less than two minutes. The reason for not helping them is there is a membrane inside the egg which has blood vessels with in it. The chick must reabsorb this blood and disconnect itself from the membrane. When the chicks hatch they will look very bedraggled. If left alone under the light they will dry out and in no time at all will be the fluffy little chicks you expected.
If possible I would try to reunite the chicks with their mum at this point. Try not to handle them too much as they are very fragile and easily stressed. If the mother hen already has some chicks she hatched herself then the best time to do this would be after the hen has settled for the night. If you simply place the chicks as near as possible to her they should wriggle their way underneath her and all being well she will accept them. If she starts to peck them then you will have to remove them and rear them by hand.