I think I can answer your question for you jake.roberts. It pure and simply comes down to need. The zoo simply doesn't need any ostrich chicks.
All ostriches in the AZA are managed as a generic group meaning they do not belong to a particular subspecies and have no conservation value. Because of this they are not managed by an SSP and carefully orchestrated hatchings are not necessary, though parentage is monitored. Add to this the fact ostriches can be purchased through ostrich farms to replace those who have passed away very easily. In the end there is no great demand for ostrich chicks to fill out other zoos' exhibits or to keep the population genetically and demographically sound. If the zoo were to allow the ostriches to keep all of their eggs and potentially hatch them could result in unnecessary mouths to feed and a strain on space until they can be placed at other zoos (because ostrich farms while fine to buy from are not a good idea to place with if you don't want the public to become outraged that the zoo is creating life to be killed).
Keepers will reduce the clutches size and if the ostriches do ok with incubating them let a few chicks be hatched. They take the majority of the eggs but leave some so the ostriches get a chance to nest, incubate and it prevents them more egg laying. So far our ostriches seem to have an issue nesting in the right place or properly incubating the eggs. Plus I believe Eunice has yet to produce a fertile egg while Miss Ellie is perhaps a little old to do so. However the keepers leave a couple and let nature take its course. If ostriches were genetically valuable or had an ssp the zoo would be taking some of the eggs aside and incubating them to ensure they survive. That's what they have had to do with the Marabou Storks since the male George likes to kick the eggs from the nest. Good house keeping is one thing, killing your offspring in the process is another. Keepers removed Archie and Zuri as eggs to prevent this and ensure that they had every chance at hatching. They were hand reared (probably because the zoo was afraid he would kick a chick out too) but other species zoo's incubate and once the chick has begun to hatch return it to its parents for hatching and rearing (think condors and penguins).
The zoo is not actively trying to prevent any chicks from hatching. Heck Eunice was brought in with the hopes of a couple of chicks every now and then. It's just thus far none of the eggs left with them have survived. Maybe one day there will be a chick or two but for now the zoo is happy to reduce clutch size (who needs 20 chicks when just a couple will do?) and let nature take its course. If chicks come the zoo is ok with that. If not well at least the adults got a chance to have the enriching experience of nesting.
The zoo took a similar approach to their emus. They would let them breed and lay eggs. The staff would then reduce clutch size to two or three and wait and see what happened. Every so often there would be an emu chick or two.
Don't forget virtually all of the births and hatchings at the zoo are part of very carefully planned SSP coordination. Of all of the species at the zoo there are only a small number of species that are not part of an SSP and most of those species are not allowed to breed (white lions being a very notable exception). If the AZA ever decides to go with a pure subspecies of ostrich, like they were when they were considering a few years back with North African Ostriches which are threatened, then you would probably see a change in the management strategy. However until that happens and the zoo gets that species it will be more of the same letting nature take its course.
Hope that helps.
All ostriches in the AZA are managed as a generic group meaning they do not belong to a particular subspecies and have no conservation value. Because of this they are not managed by an SSP and carefully orchestrated hatchings are not necessary, though parentage is monitored. Add to this the fact ostriches can be purchased through ostrich farms to replace those who have passed away very easily. In the end there is no great demand for ostrich chicks to fill out other zoos' exhibits or to keep the population genetically and demographically sound. If the zoo were to allow the ostriches to keep all of their eggs and potentially hatch them could result in unnecessary mouths to feed and a strain on space until they can be placed at other zoos (because ostrich farms while fine to buy from are not a good idea to place with if you don't want the public to become outraged that the zoo is creating life to be killed).
Keepers will reduce the clutches size and if the ostriches do ok with incubating them let a few chicks be hatched. They take the majority of the eggs but leave some so the ostriches get a chance to nest, incubate and it prevents them more egg laying. So far our ostriches seem to have an issue nesting in the right place or properly incubating the eggs. Plus I believe Eunice has yet to produce a fertile egg while Miss Ellie is perhaps a little old to do so. However the keepers leave a couple and let nature take its course. If ostriches were genetically valuable or had an ssp the zoo would be taking some of the eggs aside and incubating them to ensure they survive. That's what they have had to do with the Marabou Storks since the male George likes to kick the eggs from the nest. Good house keeping is one thing, killing your offspring in the process is another. Keepers removed Archie and Zuri as eggs to prevent this and ensure that they had every chance at hatching. They were hand reared (probably because the zoo was afraid he would kick a chick out too) but other species zoo's incubate and once the chick has begun to hatch return it to its parents for hatching and rearing (think condors and penguins).
The zoo is not actively trying to prevent any chicks from hatching. Heck Eunice was brought in with the hopes of a couple of chicks every now and then. It's just thus far none of the eggs left with them have survived. Maybe one day there will be a chick or two but for now the zoo is happy to reduce clutch size (who needs 20 chicks when just a couple will do?) and let nature take its course. If chicks come the zoo is ok with that. If not well at least the adults got a chance to have the enriching experience of nesting.
The zoo took a similar approach to their emus. They would let them breed and lay eggs. The staff would then reduce clutch size to two or three and wait and see what happened. Every so often there would be an emu chick or two.
Don't forget virtually all of the births and hatchings at the zoo are part of very carefully planned SSP coordination. Of all of the species at the zoo there are only a small number of species that are not part of an SSP and most of those species are not allowed to breed (white lions being a very notable exception). If the AZA ever decides to go with a pure subspecies of ostrich, like they were when they were considering a few years back with North African Ostriches which are threatened, then you would probably see a change in the management strategy. However until that happens and the zoo gets that species it will be more of the same letting nature take its course.
Hope that helps.
