SINGLE CHICK SYNDROME
If you set too few eggs in your incubator or it is one with a tiny capacity (yes, there are ones on the market that hold just three eggs), or if upon candling only a 3 or 4 are found to be fertile you have a risk and a decision to make.
The risk is that only one egg will hatch.
It might seem like an perfect opportunity to get the story book bond with a single animal and images may flash through your head of how lovely it’ll be if the resulting chick becomes massively friendly however the reality is some what different.
Unless you are particularly skilled at getting an animal to imprint on you but still be able to ensure it learns how to behave as the animal it is and knows how to interact with its own kind then it’s better not to try.
The reality is you will have a highly vocal (and these calls will be ones of distress) young chick that requires a lot of attention in the early days and can still be quite demanding weeks afterwards. The other harsh reality is that this one chick will still need a brooder lamp of which the running costs would normal have been spread across say 20 hatchlings.
In the end the single chick will be the most expensive chicken you will have reared both in terms of cost and effort.
The decision is do you switch the incubator off and start again with a fresh batch of eggs?
Unless there is a ready supply of day old chicks that can be added to the single bird to enable flock interaction, correct imprinting and development then it would be worth considering stopping the incubation early if the risk of a single chick hatching is high. If this is not desirable then make sure you locate a source of day old chicks well in advance of the day your eggs are due.
The alternative solution, especially if you only have small batches of eggs to hatch is to always use a broody hen in the first place, or transfer fertile eggs from the incubator to an broody hen if the numbers are low and there is a risk of single chick syndrome.