Definitely tapeworm eggs. They get them in general from eating beetles or beetle larvae. True, a standard fecal float will not pick up tapeworms in chicken, cat or dog. The pieces are too big, fecals done at the vets are looking for microscopic eggs & protozoal organisms (roundworms, hookworms, coccidia ect). Each of those round things is an egg packet containing hundreds to thousands of tapeworm eggs, but it is too large to float & stick to a slide the way single eggs are- this is how the fecal check is done at the vet's. Tapeworms are ID's by the naked eye, OR break open one of those packets and look at it under the microscope. If you want to know for sure- they are very distinctive looking. Chicken tapeworms look like -cous cous- to me. The packet is the last segment of a long worm, that breaks off and is released into the environment to infect insect. It has a two host life cycle
Tapeworms will NOT be killed by the standard dewormers that kill roundworms. Piperacillin and pyrantel and ivermectins won't kill them. Praziquantel will, plus a few others. All off label for laying hens, so be aware of that if you treat.
The tapeworms will come back again even if you treat, if your birds are allowed to eat bugs- which they love to do!!!
More than you wanted to know about tapeworms....